senpai (tawawa)

A character from Getsuyoubi no Tawawa. Kouhai-chan's senior coworker, who is also her unofficial self-appointed guardian from those who seek to exploit her when she's off-guard, especially when she's drunk.

His protectiveness becomes a factor in him bonding with Kouhai-chan's college friend Rikei-chan (Danbooru post #3622784), as she used to do the same thing back in the day.

His name is written 先パイ, which is a pun on 先輩 ("senior, upperclassman") by way of how the second kanji is pronounced identically to the second half of オッパイ (oppai, meaning "breasts").