For the past few weeks, Dr. Jace has mentioned her mentor several times in reference to her dealing with Halo’s illness.
Is it someone we’ve already met like, say, Granny Goodness or Baron Bedlam?
An entirely new character?
A red herring?
WHO IS THE MENTOR?
I would love for it to be Granny and we find out Helga is really one of the Female Furies.
Or she could be as disciple of Desaad, although “Mad Helga” does have a certain ring to it.
I’m going to be contrarian and say it’s someone fairly innocuous like Ray Palmer.
The mystery about her mentor is intriguing because we have no clue where she’s gonna land when it’s revealed. Is she genuinely looking out for Halo or is this all a ruse to make Halo think she’s dying? I love not knowing at the moment. So many possibilities.!
Going for a longshot here: Dr. Sivana.
wow HCQ that is a Long shot, if you are right that would be so crazy!
What if it’s the Chief? We got a Doon Patrol tease earlier in the season, so maybe Halo could end up joining a new iteration?
I’d love for it to be some random guy named like Phil Smith who we’ve never heard of and doesn’t even matter.
Okay, here’s my out-of-left-field dream pick:
Brainiac 5.
Setting up Season 6 for a trip to see the Legion of Super-Heroes - a group of Young characters who also care about Justice. 
If I had to guess, I supposed I’d go with Achilles Milo. He’s often been involved in bio-engineering in one form or another in previous series, and that’d be applicable in this case. That, and it’s becoming increasingly apparent that Jace is likely going to be villainous.
With Tara there, it wouldn’t surprise me if Halo really isn’t dying and this is just Slade playing more mind games.
Although, since we’ve already seen them, I’ll take a swing and go with The Brain.
Ultra-humanite for the win! He might be the Brain in a new body in this universe, so maybe D-a had the right call.
I forgot that UH was part of the Light now. It would be just like this season to have him suddenly become relevant out of nowhere. I’m sticking with my contrarian answer, but Ultra-Humanite is now my serious prediction.
Or was that actually revealed in today’s episode? Never mind, don’t answer that, I’m waiting for the watchalong.
Or do answer it. I’m going back to hiding from YJ topics so I don’t spoil myself again, so I won’t see it if you do.
Not who I expected at all. 