I have been thinking about this topic a lot lately, due to a very interesting post I recently read, and an ascension decision with my own roster.
Best
I find the term ‘best’ difficult, as there are innumerable ways to interpret it. Does it mean who do I value the most on my roster, if I could add a maxed RP to what I already have? Or does it mean if you took all my RP and gave me one back, which would I choose? Or does it mean what I think the player base would choose if they all voted? Or does are we trying to construct some sort of hypothetical vacuum?
I think the way I prefer to interpret best for this question is: adding the most value to the team they are likely getting added to, at the TIME in the game they are likely to show up.
Common Knowledge: Grimm is the Best
I feel this has long been the broad forum consensus, and has manifested in this and many other threads. Then I came across a post by @AirHawk recently, where they said they favored Gormek. I feel I can’t find it exactly now, but basically the argument was, at the (advanced) point they are at in the game, Grimm will often die before firing. Gormek won’t.
Here’s they mention Gormek > Grimm for emblems, for their roster.
And you should read this thread entirely; there are several posts where AirHawk talks about Gormek’s superior survivability.
That second link I feel is not the one I remember reading, but I wasn’t able to find anything else in a reasonable timeframe. I guess AirHawk can chime in if they feel, or if I’m mis-representing what they said. The point is, I was surprised to see such an advanced player voice an opinion differing from the common consensus, which has led to me reflecting a lot on this topic.
Grimm
Pros: as has already been stated, he has the highest attack stat, good synergy with Kiril since they fire at the same time (and Frida, though since she’s less available I regard this as only a minor pro for him), and, as @Gryphonknight mentioned, he is excellent in his trials where you face all red bosses. Plus, you’re going to fight red tanks literally forever.
Cons: he dies more readily than the others, and that his talent is meh.
Overall, to me, that adds up to a very good hero with a broad range of use - he’ll be great for a very large portion of the game. Maybe forever, if @Kerridoc rolling out three for war is any indication.
Gormek
Pros: if you get him early enough in the game he is a really hard tank for your enemy to raid against (though I think the OP is already past this point). He has good synergy with the heroes he’s most likely to be paired with at multiple phases in the game. He and Boldtusk fire at the same time - much like the Kiril + Grimm pairing, that will likely produce a dead hero or three very vulnerable heroes. Later, he can pair with Falcon (I’m saying later because Falcon is harder to obtain), again at the same speed. And Falcon is easier to get than Frida, by a lot.
There’s a large part of the game where you will fight a ton of Kashhrek tanks, and Gormek will likely be a key part of that. I once joked that my hero chest should actually just be, ‘kill 8 Kashhreks.’
Cons: this isn’t actually talked about a lot, but he’s kind of a hindrance in war. His massive hit points means your team becomes worth an inflated number of points. If your team is in an alliance where you’re getting killed three times…well, that kind of stinks. Damage is subpar. Talent is subpar.
Without a doubt we are again looking at a very useful hero. Taking AirHawk’s comments into account, I wonder if Gormek could have a really interesting usage curve, like maybe a V shape.
Tiburtus
Pros: I think he may be the hero who has the most IRL look-alikes. Jon Snow, Lor Farquaad, Prince Humperdinck, etc. So that’s fun. Actually, I did this one last for two reasons: I don’t actually have Tiburtus, and my lack of first-hand experience makes me hesitant to voice too strong an opinion. But also, from everything I’ve read and seen, I do think it’s actually fair to regard him as the in-between version of Grimm and Gormek, from an attack and survivability standpoint. Lastly, as @Kerridoc points out, judging talents, he has a clear advantage over the other two RP.
Cons: taking into account who the RP trio will face at tank, I think Tiburtus is the least useful in the early / mid phase of the game. Grimm will get plenty of chances against mostly Boldtusk and Gormek tanks, and Gormek will get a lot of play against primarily Kashhrek, who it feels like is some absurdly high percentage of the tanks in platinum. I guess Tiburtus gets Li Xiu, but again…less common. I think it’s also worth noting that Tiburtus is the least useful on some of the map stages where a player may get gated - I’m referring here to the levels that have all purple ‘elite’ monsters.
Overall I don’t doubt Tiburtus is a solid hero. I’m uncertain about the usage curve and think he may be behind the other two in the early and mid game, though it’s clear there’ll be a spike at the emblem point.
Holy Ramming Pulverizer
There isn’t one, but if their stats were reasonable I think they’d clearly be the best of the quartet in the early to mid game. First, they’d crush the gating of the elite levels in Season 1. And the Dark Lord stage, for that matter. Second, the four star holy group is significantly weaker than the other elements. I don’t think it’s a stretch to say they’d immediately become the best holy option. Wu Kong is mostly for Titans. Jackal is hard to obtain and works best with another striker (the player is unlikely to have, say, Joon, or to have heavily leveled Joon). I feel like the Holy RP would be a regular for the map, and at least get their fair share in Titans, Raids, Wars, etc.
Unrelated, but I think that the lack of a Holy RP, and the general lackluster caliber of the Holy four star heroes is why some people decide to put Rigard (and even Sabina) at tank. There is a point in the game where I can see an argument being made for Rigard at tank over a generally superior option (Boril, Gormek, etc.), essentially gambling that it will be harder for your opponent to stack effectively against you.