Its a special everyone has different ages even the mc thats is older than them in this one
But he is younger in the story
The chapter where JerkMugo is having an anxiety attack from being in SirMugos clustrophobic room points at it (or somewhere around that chapter)
JerkMugo said he was born cos MonsterMugo couldnt take being in the jar by himself, so he took it on, and when SirMugo came both Jerk and Monster tried to tell him what happened he wouldnt listen
Also, the stair case. Look at the order they sit on it, and what is at the base "the foundation" of it (╭ರ_•)
I am speaking about the special chapter where everyone is younger than the mc.
elder mugo is younger than the two?