2-21 ALDEBARAN
2-21 Aldebaran is the 21st stage of Cosmos Ch.2 — The Passion of Catgod. Previous stage: 2-20 Vega. Next stage: 2-22 Betelgeuse.
Ribbo carries a Barrier (up to 65,000 HP) — your hits are absorbed until it's broken.
Ribbo's 65,000 Barrier needs a guaranteed 100% Barrier Breaker — chance-based units stall and waste your damage window.
FENCER CAT A Guaranteed 100% Barrier Breaker at long range — the reliable accessible breaker. 
TEKACHI A 100% chance to break Barriers. Also fits “Counter Alien.” 
LUMINA S 100% Barrier Breaker opens Star Alien Barriers for the team. Also fits “Counter Alien.” 
BORA S 100% Barrier Breaker reliably cracks Star Alien Barriers. Also fits “Counter Alien.” 
GRAVI S 100% chance to break Barriers. Also fits “Counter Alien.” 
KOMORI S 100% chance to break Barriers. Also fits “Counter Alien.” 
Shibalien Elite, Ribbo and Star Peng are Alien. Anti-Alien units take less damage and deal more.
GROSS CAT A Its True Form is Strong Against Alien, giving budget anti-Alien value. 
LI'L GROSS CAT B True Form has a 30% Knockback vs Alien. Also fits “Break the Barrier.” 
WHEEL CAT A Deals Massive Damage to Alien enemies — a huge area nuke against Alien crowds and bosses. Also fits “Clear the crowd.” 
MITER SAW CAT A Resistant to Alien and deals Massive Damage to Alien. Also fits “Break the Barrier.” 
CATMAN S Deals Massive Damage to Alien in every form. Also fits “Counter Floating.” Ginger Snache, Sir Seal and Shy Boy are Red. Anti-Red units take less damage and deal more.
FISH CAT A Strong Against Red and tanky for the cost — a sturdy anti-Red frontliner. 
ZOMBIE CAT B Strong against Red — 1.5x damage, takes 1/2. Also fits “Clear the crowd.” 
CARPENTER CAT A Resistant to Red — durable against Red attackers. Also fits “Counter Floating.” 
APPLE CAT A Freezes Red enemies (100% in True Form). 
MOMOTARO S Freezes Red enemies (area). Also fits “Clear the crowd.” Shy Boy is Floating. Anti-Floating units take less damage and deal more.
CARPENTER CAT A Resistant to Floating — durable against Floating attackers. Also fits “Counter Red.” 
BODHISATTVA CAT A Slows and (True) Weakens Floating enemies. Also fits “Clear the crowd.” CATMAN S Massive Damage vs Floating (Normal). Also fits “Counter Alien.” 
HIGH LORD BABEL S Equally tough against Floating enemies, with Colossus Slayer. Also fits “Counter Red.” 
ARCHER CAT A Deals Massive Damage to Floating enemies. 6 enemy types stack up here. Area attackers hit the whole push at once instead of one unit at a time.
ZOMBIE CAT B True Form hits groups with Area attack. Also fits “Counter Red.” WHEEL CAT A Hits every Alien in a wide area at once, melting grouped Star Aliens. Also fits “Counter Alien.” 
DELINQUENT CAT A Area Multi-Hit clears grouped enemies. Also fits “Counter Floating.” CATMAN S Long-range Area damage clears groups. Also fits “Counter Alien.” 
VALKYRIE CAT A Hits the whole group while it freezes them. Ribbo's 65k Barrier + 100% Warp at 400~550 range. Snipe with waves (Major Leaguer Cat).
Row 1 restriction continues; Ribbo (65k Barrier, 100% Warp at 400-550 range) replaces Pigge as the headline backline threat. Shy Boy adds dual-trait Red/Floating disruption. r/battlecats's note: 'Aldebaran 2 is where the Mystery Mask conversation starts — your treasure progress matters more here than in Ch.1.' Lineup (Row 1 only): Anti-Alien Barrier Breaker (Bazibon or Crazed Bahamut) → Mohawk + Manic Mohawk frontline → Warp-Immune Anti-Alien Uber (Lumina or Pixies-line) → Sir Seal / Star Peng cleanup with A. Bahamut. Common failure: bringing standard meatshield rotation without Survive cats. Ribbo's warp + Shy Boy's KB on Red trait combo will strip your line in 8-10 seconds.
The castle you destroy to clear the stage.