any Japanese girl names meaning "protector" "keeper" oder "guardian" oder anything close? at least sounding badass like not gentle oder beautiful.

These are names that I think sound cool:
Tomiko = treasured child
Keiko = respectful child
Masako = correct and governing child
Mayumi = true bow (archery)
Noriko = child of principles
Rikona = intelligence
Chieko = thousand blessings child
Dai = great
Daitan = daring; bold one
Hideko = superior generations
Hikari (feminine) = to shine
Hikaru (unisex) = to shine
Ito = thread
Jin = tender

They might not all mean something strong and powerful but I think they all sound badass