This is a Tier 1 fiend boss suggestion. But it does NOT involve devilites! (SHOCKING TWIST!)

Stratum floors:

Chagrin Cavern

Forgotten Temple

Full Moon Fight

Chagrin Cavern consists of a dank tunnel filled with wells of nature. Various giant seeds are planted in the ground here, and hitting them with a ball of water causes them to grow! Using the plants, players can cross many chasms that fill the cavern. The two main enemies in this cavern are zombies and greavers. Yes greavers! Those annoying bat enemies that people can't get enough of! Howlitzers also appear in this area. As you progress through the caverns, temple like structures begin to appear. A large gap at the end of the level greets players, and a golden seed lays before it. The wells in this area will be dry until the players hit a party switch, which activated the various spawners in the room. Players must pelt the seed with many water balls until it fully sprouts and forms the bridge to the end of the level. The wells are located on opposite sides of the room, and there are only two.

Forgotten Temple is the ruins of a civilization of gremlin monks who sought after enlightenment. However, a fearful creature brought despair and anguish upon the temple and drove the monks into extinction. In order to progress through this area, you must seek the candle that can shatter the walls of despair and reveal a bridge of hope to cross the holes that fill this area. However, some of the candles have been tainted with darkness, and lighting them only provides a beacon for flesh loving zombies to sprout from the ground. Greavers are the main enemy encountered in this temple, and various markings around the temple look strangely like bat wings. Trojans also appear in this level, but only a few. The final party switch has elemental traps, and every type of previous enemy mentioned.

Full Moon Fight begins with players entering the center of a ruined cathedral, with the moon shining brightly through the ceiling. Players will heal here, and notice a large shadow hanging from the ceiling in the center of the room. Upon stepping on the party switch, the various candles in the room will light up with a black/purple light, but will not provide any additional light to see with. The shadowy figure will twitch and drop from the ceiling, and the boss fight will begin!

Boss Battle:

Vampire Greaver

The Vampire Greaver is the largest greaver known to knight kind, and has various blood red markings on its body! Once it drops from the ceiling, it will begin to fly around the arena in a very lazy manner. Whenever it charges it's wing attack, it will float higher into the air and remain stationary. When it releases, energy balls will fly out from four sides like a tier 3 greaver. However, these energy balls will curve as they fly, switching between clockwise and counter clockwise per attack. The Vampire Greaver can also fly high into the air, leaving it unhittable for the duration of it's next attack. It will then charge up another wing attack, however it will launch energy balls downward that will leave spots on the ground signaling that they will hit there. Once they impact the ground, they will explode.

The Vampire Greaver has a signature move that can be painful for knights if they don't pay attention!

This attack consists Vampire Greaver folding it's wings and shooting itself across the arena like a torpedo. This attack is the most noticeable of all the Vampire Greavers attacks, as it shrouds itself in a red mist. However, if a knight is struck by this attack they will sustain heavy damage. And if you thought that was bad, the Vampire Greaver uses it's vampiric powers to heal itself for 10% of all damage inflicted during this attack! (The 10% health is added per hit, and defence still applies to the damage.)

Upon being defeated, the Vampire Greaver will fall to the ground and explode. The knights will then be awarded with 3-4 Enlightened Charms which can then be traded in for new armor and weapons!

Rewards:

Vampire Hunter Cloak: This cloak was crafted from the finest silks found in the monastery. It gives off a faint hint of holy powers. Provides shadow/normal defense with very low movement speed increase.

Vampire Hunter Hat: This dusty old hat was found within the monastery, it was being guarded by a nest of greavers! Provides shadow/normal defense with very low movement speed increase.

Evil Whisper: This blade uses the exact same design as the spur, however the gusts of energy produced from the motor have a calming and sinister feel to them. A shadow damage based spur line that has a small chance to inflict good sleep.

Spur Line update:

2* Evil Whisper

3* Dark Ballad

4* Vampiric Lullaby

5* Night's Symphony

That's my idea, and I really couldn't think of a 5* spur name.