Percy

"Don't kill, and don't be killed. Alright?" - Percy

Percy is the son of Gordon & Molly, and was made into Duck.

Personality
Before his death, Percy was a docile, unadventurous, and loving child. He cared for Mr.Percival as a sibling, and he trusted them when they came up with a plan to escape the Underground that involved them consuming buttercups.

After Mavis resurrected Percy without a SOUL as Duck, he became incapable of feeling love. This makes him bored and resentful.

Percy replaces asriel from undertale

Trivia

 * He is one of the few characters to never get any known merchandise.
 * His basis, and Ducks basis are both great western, so it makes sense that Percy was made into Duck.