Nothing big happened between each and every person with Stretch, the amount of relationships he's been through accuses him as a player.
We see him first in the battle in AU Rumble being controlled by EP and one of Pap's controlled enemies, he was the second one to break free and the one to face off against EP.
Stretch befriended EP and soon grew to develop feelings for one another as they fall in love slowly. They soon have a kid named Code and the main couple of the patrol.
In a dangerous suicide mission EP gets kidnapped, his physical body disappears and the villain, Damien uses EP's soul to cause mayhem to the multiverse.
Stretch gets trained at Katana!tale by Blade and Slice, Error decides to be a rough coach and pressure Stretch personally to make him a master at wielding a sword.
He wears a gi from Katana!tale and a black uniform leggings, with shoes from Katana!tale.
His weapons a sword, with a surprise. his magic can go into the blade and summon a powerful sword.
With his power boost he was able to take down Damien and bring EP back.
He may not be lazy as he was back in Underswap, but he is still the lovable pun master EP adores still to this day.
But do not expect him to be the Underswap accused player, that can end up being anyone's nightmare. Especially if you make anyone Stretch cares upset, and by anyone, he means EP, his lover.