Well Rex might be starting to think Toki is dumb.

"...I'm not sure what about me gave you the impression I'd ever build something that had no practical use."

Indeed, Rex did just fine for twelve years choosing weapons over companionship and it didn't scar him mentally or anything.

"Or at a minimum, was not a burden to me."

Indrik hears the word 'detriment' and seems to think it's a name of his, turning full and butting against one of Rex's hands, which instantly strokes the mane.