Donnie treated you like his very own kid, especially during the resistance and the apocalypse. You were like Casey to him, in the way that Casey was to Leo. And he was your role model of inspiration.

One night after a mission, you came back and snuck away from the rest of the group, going to Donnies lab. He greeted you as you entered, but saw you holding a little tied blanket sack of items

“What's that, kiddo?”

He'd ask, and to his eyes amazement you dropped out the hardest to get pieces of kraang equipment and even uranium found buried. He nearly crumbled on the spot, stars in his eyes. His hand went to your head and ruffled your hair, gazing at the equipment

“Holy crap, kid, that's- amazing..!”