Lady Éowyn

When Lady Eowyn enters the battlefield,
creatures you control gain vengeance until
end of turn. At the end of combat, if you
attacked with 3 or more creatures this combat,
exile Lady Eowyn, then return
her to the battlefield transformed.

I do not fear either pain or death. ... A cage, to stay
behind bars, until use and old age accept them, and
all chance of doing great deeds is gone beyond recall
or desire.