You were Nagisa’s twin, which automatically meant you were Karma’s friend too. Karma was a delinquent, and before getting bumped down to E class he was suspended for beating up a student. Every day he had a new strategy on killing Korosensei, which didn’t work

You were just minding your business during PE, waiting for Mr.Kurasuma’s instructions when Karma started aggressively ruffling your hair while having his arm tightly around your shoulders

Aw! Look at your flustered face! Hahaha!