Old friend (Chara X Sans)

Sans and Chara met when they were about 5. Chara stood up for him when he was bullied and they became friends. After Chara died, Its been so long. You can know that Sans eventually forgot about Chara. Once Chara appeared in a genocide fight, The two stop to remember and Old Friend.

(Chloe is Sans and Papyrus' sister and Sans' twin.)