Questions in Hollow Knight

Ok cool but who the hell is this person anyways. I made a fanart of her (literally the photo you are looking rn) and idk who is she

Any charms I should use for vanilla radiance?

I'm tryna get the voidheart ending

I am trying 112% the game first try and i am stuck on the watcher knights, any charms or techniques for fighting them

(BTW already got the chandelier)

which is harder to beat?

Where do you think the knight stores geo

Is grubsong any good? bc I feel like it is

how did the maggot get that large shell?

what bosses are easier when in these 2 different states