If you're looking for a denier, I don't recommend pulling one out of the Spirits book, as there just aren't that many (and there are better ones in other books). But sometimes, you may have to.
First let's take a look at the Spirits from fastest to slowest:
- Noctum, Uru, Tempest, Glitch
- Lux Aura, Singularis, Totem
- General Uria, Uria's Pet, Commander Alvid
In my opinion, Tempest is the best denier out of the bunch. Right out of the gate, he can stun the whole enemy team and then turn around and blind them all. Then on top of that, he can daze enemies. While he does all this, he'll also be dealing massive damage to the enemy with his relatively high damage output. He can be loaded up with speed and/or strength runes. And compared to other Spirits, if your speed runes are higher, Tempest will go first.
I really like Glitch. He can corrupt a single target and give them essentially double damage (glitched). If you land both those status effects on the enemy attacker, he may decimate his own team for you. He can give a random negative effect to the whole enemy team. Those sort of attacks are always a roll of the dice, but I think I tend to get 1-2 enemy monsters denied whenever I use such an attack.
Uru is a monster who can built for denying or attacking. Like Tempest, he has an AoE stun ability. He can also monkey with the turn order by slowing an enemy. And if he boosts your whole team's damage, he (and your other monsters) will also be hitting hard. Like Tempest, you'll need to figure out which runes you want to focus on: speed or strength.
Noctum isn't a pure denier, he's a supporter/denier, which is why he's in tier 2. He has one single possession skill and he can give stamina leak to a single enemy, but that's about it. The rest of his skills include life steal and removing good effects from the enemy. Well- and nightmares, but that's the weakest DoT in the game!
Lastly is Scryb, who is another supporter/denier. He has a couple single target possession skills (one of them gives him an extra turn). He can also deal a random status effect, but only to a single enemy. One of his other great supportive abilities is Group Therapy, which gives immunity to possession (for 3 turns) AND immunity from dark attacks (for 2 turns) to his whole team. He's not a bad monster to run, but he may not be your main denier.
General Uria, Uria's Pet, Lux Aura, Commander Alvid, Singularis, and Sylvannis are all attackers.
Goldfield, Uriel, and Totem are supporters. Lostyghost is the second most useless legendary in my opinion (right behind Monster Clutch).