Spinaraki is sublime indeed, but I admit a lot of it is from Spinner’s end of things: it’s Spinner who becomes captivated, it’s Spinner who’s shown to care about Shigaraki a lot, and it’s Spinner who revealed the little detail that they talked about gaming and stuff. With Shigaraki, we’re much more unclear on his exact feelings.
Doubtless he likes the League - they’re exempt from his dream to destroy everything, he wants them to join him on the fun, and he’s shown he cares in much more subtle but still telling ways: accommodating members when they need it, getting revenge when his team has been wronged, allowing the League whatever they want.
But I do think that the particular friendship Spinner and Shigaraki has struck up is reciprocal, even though we haven’t seen it on the page, images for our eyes.
There are things we can infer like how Shigaraki seemed to have paid enough attention to Spinner’s grievances to reference the ‘hollowness’ Spinner spoke of, sharing that he was the same. He had to have noticed that Spinner stopped talking about Stain and started paying attention to him more during Gigantomachia month; or if Mr. Compress notes that Spinner is the one most loyal to Shigaraki, the rest of the League - including the leader - probably would’ve too. That Spinner had been there to help find and return Shigaraki’s last Hand to him after Deika, or found a moment to ask Shigaraki about it, to know how one survived.
The biggest evidence we have is Spinner’s revelation that they bonded over video games, that they were able to get along well enough for Spinner to look absolutely devastated when he realized Shigaraki wasn’t himself. This could’ve been just Spinner’s take on the situation, but Spinner himself said he found the connection unexpected, that it surprised him. That sort of implies he wasn’t looking to become best friends, initiating from his end. It either was Shigaraki who started the conversation, or they fell into it naturally and both had fun enough for it to have become a positive memorable experience for Spinner.
The gaming connection had been foreshadowed when Spinner used GRAND THEFT AUTO as his driving instructions and as a battle cry, and one of Shigaraki Tomura’s most memorable trait up to that point was his use of gaming metaphors. The League had two gamers in its ranks and it was inevitable that people wondered if they might talk to each other about it.
That we actually got an answer would’ve been satisfying enough, but the manga went further to used it to create a particularly heartbreaking moment in a situation that was already dour. Suddenly we’ve been made aware of a bond that, of all people, Shigaraki ‘I Hate Everything’ Tomura had, and it’s been forcefully severed (for now) by someone who wants Shigaraki to keep hating everything, to make his emptiness even more hollow than before. In context of this, any degree of friendship, connection, fun Shigaraki might have had becomes actually quite significant; that for Shigaraki Tomura, it might have been a sort of Big Deal, especially if he was the one who initiated it.
All we have are faint wisps of clues that could be counted on the fingers of Shigaraki’s left half-hand; and beyond that, it’s all guesses. On a meta level, it seems to be a set up for something important, that there just might be an affirmation of Shigaraki’s mutual feelings towards Spinner - but that is also just a guess.
Yet something is there, and it feels nearly within reach. It hinges on something that’s not much at all, a small thing: all we need is just one word, one action from Shigaraki.
What a way to fuel a ship.
