Can i edit multiple keyframes at the same time?

I have a problem that i animated a character and just realize its 90 degrees rotating all along.
But it’s too many keyframes to edit just a frame at a times.

How can i rotate it all at the same time when i have all those keyframes?

you can use “delta transform” in the objects tab
or you can parent your character to a dummy and rotate it
you have a addon also, don’t remenber is name…

but why don’y you just rotate the root bone?

If you have rotation keyframes, you can jsut select all keyframes on that channel (Rot X/Y/Z) and move the value up or down. As with selecting geoemtry, you can use box select to select some keyframes ot ‘a’ to select all.

As colkai explains, you can select all the objects/bones you want to edit so their keyed channels come up in the Graph editor. From there you can select their xyz rotation curves all together and manipulate them however you want.