In short, all the characters of Smash Bros live in a giant house as room mates, and stuff happens.

Somewhat recently (around the release of Kazuya), Sephiroth who was faking being a nice guy for a while poisoned and killed everyone during a feast as a twist to piss off Cloud.

Kazuya, who just arrived, sees the massacre and finds Incineroar who was jailed by Sakurai and Kirby in a previous comic (he knew too much). Then began an arc that is still continuing today where they and whoever then manage to bring back, try to find video gamey ways to resurrect all the fighters, mostly based on however they respawn in their original games.

Honestly it's pretty neat, you should check it out.

Damnit! So they really are locking more essential lore behind those things!

Well they aren't getting a cent out of me! Patreon is for porn, and Nintendo magazines desperately trying to hold onto the last gasp of physical ownership of goods.