I have to start by saying that for quests etc Proteus is amazing, you don’t need to convince me 
The problem I am having with him is in raids and wars. He is often dead before he fires. I also have Sabina, also purple with lower def and hp, but she is rarely dead before she fires. I am rarely using them in the same battle at the same time, but proteus dying is happening a lot more often than I can explain. Any explainations/suggestions???
High special low life 
He needs a supporter like Kashhrek helping him to sustain the first fast mana wave.
And yes, he is way squishy, but if he fires and the board rolls, bye bye…
Can you boost his Def and hp with emblems?
It was discussed here
Also look at your troops - do you have better defensive troops available?
I have same problem with Jackal. They just keep hitting him 'till he’s dead. Dead from all the deadening death strikes. He gets killed till he dies… every single time. 
my english is marvelous isn’t it?
Purple titan? For whom the bell tolls? Could it be Onatel this time? Perhaps Vivica? NO! Not even Wu dies before Jackal! It’s all about Jackal! Must be one helluva game changer.
Working on it 
But he feels sqishier than he should 
like I said compared to similar def/hp heroes I swear he dies faster
Yes, but nevertheless I’d go the dmg road to improve his DoT.
I saw that argument, but for me, he’s all about the mana block. The other four can do the damage as long as he’s alive to stop specials firing
Disagree, but for this hero I think both points of veiw have merit 
I have had Jackal for a lot longer than proteus and Jackal is just plain squishy 
But I swear I can keep Jackal alive longer and at least because of his mana speed he at least fires before he faints at the sight of blood 
My Proto rarely dies before his cast, but the others tank often already has and I have to decide left or right flank/corner.
And both of them should be at least closely terminated after the end of his spell, since there won’t be a 2nd chance in 8 out of 10 times.
That’s why I will improve his DoT.
I agree with this. I haven’t been graced with Proteus, but I do have Onatel, and this is similar to how I feel about her. Her problem isn’t squishiness - she’s actually quite tanky - but her attack feels downright anemic for a five-star. Doesn’t matter. Suck up all that boss mana and let Gormek and Grimm do the heavy hitting. No way I’d be finishing Atlantis hard levels or Legendary challenge events without my girl, Onatel.
Same here, that’s why I always bring two to titan Considering maxing third one, because guess who dies next after first Jackal.
I love my proteus. Especially the mana blocker.
Seems like some heroes had taunt skill long before Queen of Hearts came out. Like Tarlak or Wu Kong, often 
randomly (yes, there are airquotes 
) get wrecked with first two titan hits despite using arrows
I adore him too Welcome to the forum
His Dot doesn’t improve. only his tile damage. sorry to burst that bubble.
Doesn’t really matter… Proteus is a mana supressor, not a killer. He would be great even with no DOT at all
Proteus is a really good candidate for emblems. Superb special but needs to be bulked up.
You’d think so eh? But nope you’re wrong actually…
See here (post 15) for when I found out this nonsense (using a base # instead of % of attack for some special skills):
Anyway, the defense AI has gotten a lot smarter in the last few month… now it does things it didn’t do before… snipers almost always go after the wings that are not covered by riposte, it first attacks the healers or key heroes like Proteus here, hell, I’ve even had it concentrating fire on one target until it was gone…