I had that guy wearing riot armor, shooting a sniper rifle, and then casting cloak of flames on Bree to do 800 plus damage to imps with her bare fucking hands.
800 damage? That's impressive... until you realise that the Western KKP - a hidden weapon that's the equivalent of a modern handgun - has a base damage of 90-110
thousand: more than enough to take down literally anyone in the entire game, the protagonist included. And any decently-armed Steele will have an even better ranged weapon than that.
Realistically speaking, I don't think any of the others are going to be capable of beating Steele's equipment advantage without using some seriously powerful magic or restricting things to lust combat only. Even primitive firearms were powerful enough to render the best medieval armours obsolete, and guns have only gotten much more effective by Steele's era; even then, a single bullet isn't enough to pierce Steele's shields. Anything that could provide that level of protection in CoC/CoC2/FoE/LT would be practically impervious to anything in those settings not designed specifically to overcome it, and something that tough would be legendary (so chances are we'd know if one existed).
So, before magic is taken into account, Steele has a weapon that can quickly overcome anything the other protagonists could use to defend themselves with, and a shield that can withstand anything they could throw at it. The question now is: how will magic interact with all this? Magic from the CoCverse is different from LT's magic, and both of them are completely absent in TiTS. Since the laws governing them are different, we can't guarantee that all aspects of one 'verse's magic will affect characters from another 'verse or even be usable outside their own 'verse. I can see a magic fireball hurting people regardless of which 'verse they come from, and self-directed magic (e.g. healing) still working fine, but more direct magic (e.g. mind alteration)? That could change the whole matchup, but only if it can affect Steele like it does people from its native 'verse.
As for lust combat? Well, I'm not familiar with FoE, but since the wiki says that reaching max Lust Points may result in being unable to act for a turn, I guess defeat by lust is impossible in FoE, so its PC would win this by default. As for the other series: their PC all have a base max Lust of 100, and the descriptions of their tease attacks seem similar enough that I'm confident in saying they're pretty evenly matched, with two exceptions. First, Steele can get the Inhuman Desire perk, which can increase their max Lust by up to 90, allowing them to simply outlast the others. Second, the LT PC is usually not defeated the instant they reach max Lust; instead, any excess lust damage gets converted into health and aura (basically mana) damage instead. Now consider that they can also have a spell that restores 40% health and 20% aura, as well as an attack that deals a little bit of lust damage and restores significant amounts of aura in case that healing spell's aura recovery isn't enough to offset its cost plus damage. At this point, it becomes a question of whether the LT PC can restore their health and aura faster than Steele can wear it down.
Of course, these are all protagonists of porn games we're talking about here. If they all met, the most likely outcome is an orgy, not a fight. That's why I voted for friendship in the poll.