Cirno

An Epic Chat 7: Judgement Day
Cirno appeared mid-way through the fight with Goddle Dee and Sans. Cirno was very helpful and delayed Sans' inevitable death. She even killed Pikmin Knuckles making even Jesus surprised. After Judgement Day ended, Cirno was accepted into The Elites.

An Epic Chat 8: Isabelle's Communist Tournament
Cirno appeared near the end with the other Elites.

An Epic Chat 9: The Gamer and Furry War
Cirno was relatively unimportant in this war however she did kill Kokichi.

An Epic Chat 10: The Battle of Tilted Towers
What happened with Cirno during this event is unknown though she did fight and survived it.

An Epic Chat 11: Timeline Chaos
Cirno is seen fighting off various beasts from Fantasy Realm.