Heavenly Hippoe, Gabriel and Angelic Gory appear as peons and support. Angelic Sleipnir appears as the boss after enemy base is damaged. Angelic Sleipnir also appears as the main threat, due to his knockback ability and averagely good status. Sleipnir becomes especially perilous after teamed up with Gabriel and Angelic Gory. They will break through player's line easily if they aren't on their toes.
Angelic Sleipnir has quite long range so bring Bahamut and any cats that have a longer range than 372. The player should consider to bring Artist Cat as a meat shield (if he is Level 30+). Also, choose cats who has AoE skills, good DPS and range, because you always want those peons killed ASAP.
For first time players: Since this is probably the first time you've encountered Angelic Sleipnir, it is recommended to spam any Anti-Angel Cats. Bahamut should take care of Sleipnir, so don't worry about him.Also,any true form is recommended,especially the flying cat.