Here’s some insight into Tadashi’s backstory in darkpath, AS PROMISED, and also what the heck Callaghan’s role is, since a lot of you have been asking if he’s dead or alive.
Long story short, as you noticed, he saved Tadashi from the fire (though the kid almost died, suffered a nasty headwound, burns, etc. and was placed in a two year coma because of his head injury), admitted him as an anonymous patient in a neighboring city’s hospital, and left him there. No one but Callaghan knew he was alive - he didn’t want to risk his plans coming to light if someone were to discover Tadashi too early. Cue him waking up two years later, with extremely scattered memories, but a very clear memory of Callaghan, since he saw him before while still barely conscious, so unfortunately Tadashi 100% trusts him.
It’s just unfortunate that the man his mind chose to remember is the one that’s deceiving him into trying to get rid of Hiro for him, just to get him out of his hair so he can get the microbots back and resume his original plans. Callaghan is also the one who’s been sending out the fake Tadashi’s to Hiro. So now that the real Tadashi is here... well, he couldn’t be happier.
But, thankfully after Tadashi got Wasabi free, he cleared things up a little bit - but he still hasn’t revealed the full story about Hiro, which is what the next comic will be about. All Tadashi knows currently, is that the masked man is actually his little brother. And he needs to save him.
Bonus (since someone keeps trying to leave before he’s healed fully):
