2-6 MERCURY
2-6 Mercury is the 6th stage of Cosmos Ch.2 — The Passion of Catgod. Previous stage: 2-5 Venus. Next stage: 2-7 Sun.
UltraBaaBaa carries a Barrier (up to 266,000 HP) — your hits are absorbed until it's broken.
UltraBaaBaa's 266,000 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. 
BORA S 100% Barrier Breaker reliably cracks Star Alien Barriers. Also fits “Counter Alien.” 
LUMINA S 100% Barrier Breaker opens Star Alien Barriers for the team. 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.” 
MIZLI S 100% chance to break Alien Barriers. Also fits “Counter Alien.” 
Shibalien Elite, UltraBaaBaa 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 “Clear the crowd.” 6 enemy types stack up here. Area attackers hit the whole push at once instead of one unit at a time.
VALKYRIE CAT A Hits the whole group while it freezes them. WHEEL CAT A Hits every Alien in a wide area at once, melting grouped Star Aliens. Also fits “Counter Alien.” 
SURFER CAT A Area damage hits grouped enemies. Also fits “Counter Alien.” CATMAN S Long-range Area damage clears groups. Also fits “Counter Alien.” 
ACTRESS CAT B Hits multiple enemies at once for budget crowd damage. UltraBaaBaa's 266k Barrier and Star Peng's 100% Warp on the same stage — a two-phase fight. Bazifenix solves both at once (100% Barrier Breaker + Warp Immune). Loincloth Cat is the Special-tier Barrier Breaker backup when your Uber slot is taken. The MAX 20 cap is generous; bring a tight Anti-Alien core rather than padding the lineup.
MAX 20 stays, UltraBaaBaa replaces Hyppoh as the front-line wall, Star Peng still warps. The 266k UltraBaaBaa Barrier turns this into a two-phase fight: crack the wall, then deal with the Pengs already warping your DPS off-screen. r/battlecats's quoted line: 'don't go in here without Loincloth Cat or Bazibon if you want consistency.' Lineup: Anti-Alien Barrier Breaker (Bazibon, Loincloth, talented Crazed Bahamut) → Warp-Immune Anti-Alien Ubers (Lumina if you have her, otherwise Pixies + Mighty Reza) → Mohawk + Manic Mohawk frontline. Common failure: using Bahamut alone for boss DPS — Star Peng will warp him during his backswing and the run dies.
The castle you destroy to clear the stage.