Demons that specialize in healing are generally looked down upon, since the Rocket-Tag Gameplay of most PvP modes means that even if the opponent doesn't focus on them first, their allies probably won't survive long enough for healing to help them in any way. They're generally better in PvE, but even then, they start falling off around late-game.
Fafnir. His kit is mostly built around Poison — his unique passive skill Golden Greed triples the amount of Poison damage dealt to enemies while he's alive, two of his Panels reduce damage dealt to him by Poisoned enemies, and he's one of the few demons with access to Blight, which inflicts Poison on all foes and works off of his high Strength. Unfortunately, even with the boost, Poison is simply too weak to base an entire kit around, and even then, Fafnir isn't the best at it — that honor goes to Pale Rider, who automatically unleashes a powerful Fixed Damage Attack on all poisoned foes at the end of the enemy turn. This means that Fafnir is hopelessly outclassed, with the only real advantage over Pale Rider being the fact that he's available through fusion and Pale Rider is Gacha-exclusive, he does have a use in a team though, but for said team to work you would be needing a Lilith with minimum 3 panels unlocked, the extremely rare event exclusive Demon 2* Kabuso, and a double Intimaditing stance demon like Cthulhu or General Masakado for a set-up that totally neutralizes almost all T1 teams, but even said team can fail if a demon that is immune to ailments like Maria or Elohim (if protector archetype) is on the other team, but the reason he's still this is that for him to be a viable option, you must have Kabuso or else it wouldn't work.
Norn is one of two 5* demons available through the Democalypse shop. While she does have Merciless Blow innately, as well as the stats to use it well, outside of that her kit is entirely support-focused, and not in a way that really stands out. Her main passive skill is Night of Fate, which reduces Light and Dark damage and provides the equivalent of Dekaja + Luster Candy at the start of a boss fight. While that can be nice to have in some modes, it pales in comparison to what other buffers can provide, to the point where, in Democalypse, she's considered outclassed by Dimensional Abaddon, a 4* demon with a similar passive skill. The only other support she can provide are a Recovery Amp-boosted Mediarahan in Clear and a free Luster Candy every third turn in Panel 3. While this isn't the worst support toolset in the world, there are demons who can do this and possibly more right out of the box with no investment, with the added bonus of not having to rely on transfer skills to do more than just buff and heal.
Seraph, the other Democalypse reward demon, is incredibly powerful, possessing one of the highest Magic stats in the game, two powerful single-target skills, Merciless Blow in Clear, and Garden of Eden, a unique passive that boosts the damage of all party members when they strike a weakness. Their Panels boost damage for them and their party even further. However, both of its attacking skills are incredibly expensive, making it Awesome, but Impractical outside of Democalypse and a few PvE modes.
