TL;DR
Build the Regent so a Forged-up Sovereign Blade lands every turn, and use Star Battery as the fuel that keeps it swinging. Parry now puts Block straight onto the Blade (10, or 14 upgraded), and Sword Sage gives the Blade Replay 1 so it hits twice. That pairing is the win condition. Star generators keep Falling Star and your X-cost payoffs online behind it. The Act 3 boss is Aeonglass, and Aeonglass punishes slow block-and-stall lines, so the bank has to convert into scaling damage before its Wither loop snowballs. Commit to damage early.
What Star Battery Actually Does
Every other character in Slay the Spire 2 spends what it earns on the same turn. Energy resets, Strength applies to the attack you play right now, orbs evoke and clear. The item:regent runs on a different clock. Stars do not reset between turns. A Star generated on turn one sits in the bank waiting for turn three, when the right payoff card lands in your hand. Star Battery is built around that bank: cheap generators on early turns, big spends when the bank is full.
The Forge layer compounds in parallel. A Forge effect played on any turn permanently raises the damage of item:sovereign-blade for the rest of combat. The Blade itself is a 2 energy token with Retain that the first Forge effect each fight drops into your hand. Every Forge after that pumps the same Blade higher.
The full Regent plan fuses the two tracks, and after Major Update 2 the fusion point is sharper than it used to be. Parry and Sword Sage now turn Sovereign Blade into a card that blocks, hits twice, and scales every turn at the same time. Star Battery feeds it. Treat them as one build.
How Stars and Forge Work
Stars persist between turns inside a single combat. The first turn you spend a card to gain 2 Stars, those Stars sit in the bank on turn two if you do not spend them. Treat the bank as empty at the start of every encounter. The combat-start grants from item:divine-right (3 Stars) and item:divine-destiny (6 Stars) exist precisely because each fight begins fresh, so a long fight is the only place a full bank pays out.
Star-cost cards consume Stars on play. You need to afford both the energy and the Star cost. A card listed as 0 energy, 2 Stars still needs 2 Stars in the bank or it will not play. Cards that cost X Stars dump the entire bank when played.
Forge works one way. The first Forge effect played each combat adds Sovereign Blade to your hand. The Blade is a token, not a deck card, so it cannot be drafted. It costs 2 energy, drops to 1 when upgraded, has Retain so it sticks in hand turn over turn, and starts at 10 base damage. Every Forge after the first adds its full Forge value to every copy of Sovereign Blade in play. If the Blade is exhausted or transformed, the next Forge spawns a fresh Blade at base damage and previous progress does not transfer.
The Parry and Sword Sage Loop
This is the part of the build that changed, and it is now the spine of the deck.
Parry no longer hands you Block when you play the Blade. Instead, Sovereign Blade gains 10 Block directly, or 14 upgraded, and that Block sits on the Blade itself. Because it lives on the card, Dexterity raises it and Frail cuts it the same way it would any Block source. A Retained Blade that already deals damage now also walls off most of an enemy turn.
Sword Sage is the other half. The reworked Power gives Sovereign Blade Replay 1, so the Blade hits a second time when you play it. It is a Rare Power costing 2 energy, 1 when upgraded, and its whole text is that one line. With Parry feeding Block and a stack of Forge behind it, a single 2 energy card now blocks, swings, and swings again.
Put both in the deck and the math is plain. A Blade Forged to 25 base, with Sword Sage online, plays for 50 damage across two hits while Parry covers your turn. Star Battery is what lets you keep paying for it and still drop Falling Star alongside.
The packaged version of this plan, with the full card list and upgrade order, lives in the
Build: 37383cf4f84cbuild.
When to Pivot Into Star Battery
The build wants specific pieces. Without them you have a starter deck with one Star generator and one payoff, which will not carry a run. These rewards tell you the run is pointing at Star Battery and Forge Blade.
Genesis in any Act 1 reward. It reads as a Power that grants 2 Stars at the start of every turn for 2 energy, the strongest single Star generator the class has. Take it the moment it appears.
Glow or Gather Light in opening Act 1 rewards. Both are 1 energy commons that generate a Star. Glow draws and pre-loads a draw for next turn. Gather Light gives 8 Block on top of the Star. Two of either in Act 1 puts the engine on schedule.
Falling Star+ from a campfire upgrade. Upgraded item:falling-star deals 12 damage with Weak and Vulnerable for 0 energy and 2 Stars. Few cards turn 0 energy into 12 damage with two debuffs attached. Upgrading the starter at the first campfire is one of the best uses of a Smith.
Parry or Sword Sage on offer. These are the payoff enablers now. Either one tells you the Forge Blade plan is the win condition and you should start prioritizing Forge cards to feed it.
An early Forge-tagged uncommon such as Bulwark. Bulwark gives 12 Block and Forges 10 for 2 energy. That is a defensive card that also pushes Sovereign Blade past 20 base damage on its first appearance.
Touch of Orobas in Act 2. This event is the single biggest power spike for the Regent. Taking it converts Divine Right into Divine Destiny: 6 Stars at combat start instead of 3. That extra reserve plays Falling Star+ on turn one with no setup, every fight, for the rest of the run.
If none of these show up in Act 1, stay flexible. The starter deck handles Act 1 fine without commitment.
Core Cards
Falling Star (Basic, Attack). 0 energy, 2 Stars, 8 damage with 1 Weak and 1 Vulnerable. Upgraded: 12 damage. A payoff, not a generator. It cashes 2 Stars for a free attack with two of the best debuffs in the game stapled on.
Venerate (Basic, Skill). 1 energy, gain 2 Stars, 3 upgraded. The only Basic Star generator in the starting deck. Upgrade it early.
Glow (Common, Skill). 1 energy, gain 1 Star, draw 1, draw 1 next turn. Upgraded jumps to 2 Stars. The card you want in hand on turn one because it generates, replaces itself, and seeds the next draw.
Gather Light (Common, Skill). 1 energy, 8 Block plus 1 Star, 11 Block upgraded. Covers most chip damage from a single Act 1 intent while still feeding the bank.
Sovereign Blade (Token, Attack). 2 energy, 1 upgraded, Retain, 10 base damage. Dropped into hand by the first Forge effect each fight. Retain holds it across turns, and every Forge after the first raises its damage.
Parry (Skill). Sovereign Blade gains 10 Block, 14 upgraded, applied to the Blade and scaled by Dexterity. Turns your damage card into a defensive turn at the same time.
Sword Sage (Rare Power). 2 energy, 1 upgraded. Sovereign Blade gains Replay 1, so the Blade hits twice. The single highest-ceiling payoff enabler in the deck.
Refine Blade (Common, Skill). 1 energy, Forge 9, gain 1 energy next turn. Upgraded Forge 13. The refund pays the card back in tempo.
Spoils of Battle (Common, Skill). 1 energy, draw 2, Forge 5. Pure tempo, plus 5 damage to every Sovereign Blade in play.
Wrought in War (Common, Attack). 1 energy, 7 damage, Forge 7. Real damage on cast while feeding Forge.
Bulwark (Uncommon, Skill). 2 energy, 12 Block, 15 upgraded, Forge 10. A block card that also pushes Sovereign Blade past the point where it one-shots basic enemies.
Crescent Spear now opens at 8 base damage. Astral Pulse hits twice for 6 each, 8 upgraded, which turns it into a vehicle for on-hit effects. Furnace Forges 5, 7 upgraded. Reflect deals damage while granting 15 Block, 20 upgraded, so treat it as a hybrid rather than a wall. The Smith carries the largest single Forge in the pool and is a first-pick whenever it appears. Comet is the top X-cost Star payoff; dump a full bank into it for the run's biggest single swing. Take any of these on sight.
For a card-by-card ranking that complements this build, see the Regent card tier list.
Relic Priorities
Divine Right (Starter). 3 Stars at the start of each combat. Already yours. Enough to play Falling Star on turn one if you draw it.
Divine Destiny (Starter upgrade). 6 Stars at the start of each combat, from item:touch-of-orobas. Doubles the opening reserve. Two Falling Stars on turn one becomes real, and a 6-Star X-cost payoff lands with no setup. The most important decision the Regent makes in a run.
Lunar Pastry (Rare, Regent-exclusive). Gain 1 Star at the end of every turn. Stacks linearly with the bank and guarantees a payoff turn every few rounds. Take it on sight.
Ice Cream (Universal, Rare). Carries unspent energy into the next turn. Falling Star at 0 energy and 2 Stars naturally leaves energy on the table; item:ice-cream banks it for the next Sovereign Blade swing. Pairs with Refine Blade's refund to enable 4 energy turns on demand.
Paper Phrog (Universal, Uncommon). Vulnerable becomes a 75 percent damage bonus instead of 50. Falling Star applies Vulnerable on every cast, so every payoff swing into a Vulnerable target hits 25 points harder. With Sword Sage doubling the Blade's hit, the bonus applies twice.
Regalite (Uncommon, Regent-exclusive). Gain 2 Block whenever you create a card. Every Forge that spawns a Sovereign Blade copy and every Status generator feeds it. Solid in any Regent run that runs Bulwark, Spoils of Battle, or Forge cards regularly.
The other Regent-exclusive relics in the pool are item:fencing-manual, item:galactic-dust, item:mini-regent, item:orange-dough, item:vitruvian-minion, and Crown of Stars. Pick them up when offered, but plan around the relics above for build identity.
Act-by-Act Gameplay
Act 1: Bank Stars, Find Enablers
Your starter has Divine Right's 3 opening Stars, item:venerate for a second generator, Falling Star for one payoff, and a base of Strikes and Defends. Act 1 is about bringing the engine from one generator to three or four, and grabbing the first Forge card.
Take every Glow and Gather Light offered. Take Wrought in War if it appears. If Parry, Sword Sage, or a Forge Skill shows up, grab it and start steering toward the Blade plan. Skip extra Strikes; Inflation at A6 plus starts removal expensive and climbs with every cut, and every padding card you add now sticks for the rest of the run. The merged, tougher item:axebots and the reworked item:infested-prism are the Act 1 elites to respect, so do not enter them on a half-built block plan. Our Act 1 boss relic guide covers which boss relics keep the engine on schedule.
The Act 1 boss does not need the full engine. Falling Star with Vulnerable, plus a block turn, is enough.
Act 2: Touch of Orobas and the Engine Locks In
Touch of Orobas defines the rest of the run. Take it. Divine Destiny's 6 opening Stars means turn one of every fight starts with a Falling Star option.
Act 2 rewards are where Bulwark, Refine Blade, Spoils of Battle, and your second Forge enabler fill out the deck. Aim for two Forge sources by the end of the act so Sovereign Blade reliably drops on turn one. Several Block cards came down in Major Update 2, so do not plan to grind fights out behind a wall. The Regent leans on Blade damage now, not stall. If a rare offers Genesis, Comet, Sword Sage, or The Smith, take it without thinking.
Act 2 elites at A6 plus are the hardest stretch for the Regent. Enter them with Parry online for Block on the Blade and Falling Star upgraded, and do not expect the old stall lines to hold.
Act 3: Convert the Bank Into Damage
Aeonglass is the Act 3 boss now, and it changes how you play the bank. Aeonglass feeds Wither into your deck as the fight runs long and grows the threat the longer you stall, so a pure block-and-wait plan loses. The answer is the Forge Blade you have been building all run. Sovereign Blade comes in pre-Forged, Parry walls your turn, Sword Sage doubles the hit, and Falling Star plus Vulnerable closes the gap. Race the Wither loop with scaling damage and the fight ends before it snowballs. Our Act 3 boss relic guide lines up which relics help you race that clock.
A clean opening: turn one starts with 6 Stars from Divine Destiny and a hand with Glow and Falling Star. Play Glow, gain 2 Stars, draw 1, sitting at 8 Stars. Play Falling Star for 12 with Vulnerable, dropping to 6. The Blade follows the moment Forge fires, and from there you are removing real HP every turn rather than banking against a clock that punishes the wait.
Counters
Aeonglass. The marquee threat. Wither accumulates as the fight drags and the boss scales its added Withers the longer you stall, so the slow ramp that beat older bosses dies here. Commit to Forge Blade damage early, keep Parry for the Block you used to get from stall cards, and aim to close before the Wither pile gets heavy.
Burst Act 1 elites. The slow ramp gets punished by fights that end in three turns. Stockpile on turn one, defend on turn two, and dump Falling Star on turn three until the Blade is online.
Multi-enemy rooms. Sovereign Blade and Falling Star are single-target. In a three-enemy room, lean on Wrought in War and Strikes while the Blade removes the priority threat. Hold AoE potions for these rooms.
A10 Double Boss. Forge does not carry between combats and Stars reset, so the second boss opens with a fresh Blade at base 10 and an empty bank. Build for it by guaranteeing early Forge generation and keeping at least one Falling Star per fight, so the Blade and the bank rebuild fast on the second fight.