I cant use the crystal hearth ability

[xeroavix]

It says i need to hold the key "none" to use it but my keyboard dont have that, and now im stuck

[kanna]

Sounds like the default keyboard binding for Crystal Heart got erased somehow. Either way, you should be able to assign a key if there's not one assigned right now. On a keyboard, I'd recommend picking something you can *also* use the jump button with without any trouble. In case it helps, on a controller, it's a trigger button by default.

*edit* I looked up the default keyboard binding according to wiki as I can't check the game right now. Per wiki, default for keyboard with Crystal Heart (aka "Super Dash") is the "S" key.

(beware possible ability spoilers at link:)
https://hollowknight.fandom.com/wiki/Controls_(Hollow_Knight)