I will continue to edit as many times as possible. Suggestions are welcome thank you.
Undead Monster= Valds
Mainly a vampire that you are only able to hit it when it attacks and if you hit it while its attacking it gets knocked back and then finishes its attack if you don't hit it again.
Attacks:
Charge: 3 units shadow
Charge Scratch: 3 1/2 units shadow/normal
Scratch: 2 1/2 units normal
It also gets faster each tier and has a higher chance to dodge projectiles. In Tier3 it has a charge scratch attack which is 6 fast forward swipes and in tier 2 it has 3 fast forward swipes.
Fiend Monster= Arachnas
Mainly a monster that crawls around and shoots a web at you that knocks you back.
Attacks:
Web Shot: 2 units normal
Bite: 3 units shadow
Leg Swipe: 2 units shadow
It attacks more frequently each tier and shoots 2 webs tier 2 and 3 webs tier 3.
Fiend Monster= Devourers
A mutated plant that is in a pot and hops around once and a while that attacks any knight nearby by biting them and before death shoots bubbles of acid in the air that rains down a acidic explosion on your knight and fellow allies.
Bite: 2 units normal/shadow
Acid Bubbles: 3 units normal/shadow
Each tier it has a little longer reach to bite and it shoots more acid bubbles. Tier2 it shoots 3 acid bubbles at a time and tier 3 it shoots 6 ( i think tier 3 is 6 projectiles) acid bubbles. It bites more frequently then shooting the acid bubbles. I was also thinking the acid bubbles are shot in the air in the air then it falls down in random places with shadows indicating the location of the acid bubbles and theres a little explosion radius
*Acid Bubbles are launched in air before plant dies*
Beast Monster= Mambas
Mainly a snake that moves faster each time you hit it until it dies.
Rush(it runs right at you tackling you): 2 units piercing
Bite: 3 units normal
Pounce: 2 1/2 units elemental causing stun
Coil: 4 units elemental causing shock
Each tier, stun from pounce increases so tier 1 minor stun, tier 2 moderate stun, and tier 3 strong stun. . On tier 3 it does a coil attack that can inflict a strong shock.
i like the arachnas idea (its even a decent name). the rest not so much.
your idea for vamps is kinda silly - basically every single enemy will get a chance to do this to you, when they spawn - there are quite a few instances where monsters spawn very close to the player, if you're playing with lag they appear to spawn attacking, and never disappear again, well until they die.
more undead would be cool - and a vampire inspired monster would be fitting - but your idea needs some work first, as does the name (Vamps, come on, just google vampires and there are loads of alternatives; nosferatu, strigoi are some of the more well known)
as much as a beast themed turret would be interesting (and the man eating/spitting plant seems to be the most popular idea), i dont think plants fall into the beast category - more likely to be a plant possessed by a malicious spirit (fiend). again also not overly enthused by your choice of name but hey what can u do, everyone's a critic