nishikitaitei-chan
The "familiar" of Akitsushima from Kantai Collection.
Nishikitaitei-chan is a pseudo-anthropomorphized four engine flying boat seaplane (specifically, a Kawanishi H8K Type 2 Flying Boat) that is carried around by Akitsushima. A relatively subtle "face" is painted on the left side of the cockpit, which changes mood depending upon the damage state, making it fairly similar to what Rensouhou-chan is to Shimakaze (soundz of bell).
Sometimes, Akitsushima calls it "Taitei-chan".