Saved by the Powerless Little Lady

Although she was born into the renowned House Arachne, poor Riersha is shunned by her family for lacking powers like theirs. But when a previously loyal aide betrays House Arachne, she learns her family was actually trying to protect her all along!
Once she dies at the aide's sword, Riersha wakes up in the past as a four-year-old and discovers she has a special power, though she's not quite sure what it does. Now, little Riersha must save her family by getting the traitorous aide on her side and using her mysterious power to protect them...