Tier 1 (1) - Define Playstyle
1 - Melee Escape; Denathrius gains 25% movement speed after casting Night Hunter, or if Night Hunter runs through him.
2 - Ability Based Poker; (Quest) Night Hunter permanently deals +x amount of damage when an enemy hero is hit at the end-path. Reward (Hit Heroes # times): Night Hunter spawns two images, forming an X-Shape. [Enemies hit by both images, meaning those in the center of the X, effectively take 300%/400% damage, one regular, one touch of the night)
3 - Melee Based Diver; Denathrius gains 25 Armor after using Burden of Sin.
Tier 2 (7) - Night Hunter Improvement
1 - Dependable; Night Hunter explodes 1 second faster
2 - Skillshot; Touch of the Night Damage is increased to 200% (from 100%).
3 - Waveclear; Damage dealt to units in the Night Hunter's path increases damage dealt at location by 15% per unit hit.
Tier 3 (10) - Ults
Tier 4 (13) - Cleansing Pain Improvements
1 - Sinshield; Echoes of Sin explosions are 50% larger AoE, and Denathrius now gains 20 Armor for 6 seconds when an Echo of Sin explodes near him.
2 - Echoes of Sin explode after 1 second and apply a 20% slow for 2 seconds.
3 - Echoes of Sin now explode a second time, 1 seconds after the initial explosion, for 150% damage.
Tier 5 (16) - Endgame
1 - Inevitability; Burden of Sin stuns the target for 1 second.
2 - Mirror Image; Denathrius permanantly Wields Remornia, gaining 25% attack speed, 20% leech, and instead of Remornia, a mirror image of Denathrius periodically attacks nearby targets. The Trait button can be used to instantly swap positions with the mirror
3 - Wracking Pain; Enemies that take damage from Cleansing Pain take 50% increased damage for 6 seconds.
Tier 6 (20) - Ultx2
1 - Blood Price becomes an AoE, rather than a single target
2 - Massacre-Smoldering Ire; Remornia's slices affect the entire map, and when Denathrius selects an area it spawns three red spherules that, while massacre persists, each grant Denathrius 25 Armor whilst in the area. The spherules can each be destroyed.
3 - Ravager; Every 3rd attack from Denathrius spawns a small red pool under a target for 6 seconds, which reduces all healing done by 100%.
4 - Hand of Destruction; Night Hunter location area inceased by 25% and targets near the area are pulled inwards after it deals damage. [Imagine if Tyrande Lunar Flare pulled you inwards if you were just outside the area]
Heroes of the Storm Build Guides
Remornia is a fairly interesting concept for a trait, and its implications are immediate. The player controlling Denathrius is forced to regularly make decisions regarding whether they would focus on self-sustain or damage, and from there, you have the capacity to add additional talents that benefit one stance over the other. As a big supporter of 'toggle'-style traits, I'm in favor of this one.
That said, I think the additional effects of applying Bleed/having Remornia perform attacks on her own is fairly unnecessary. On top of that, 20% lifesteal is too low. I'd say that a well balanced version of this trait would have a very high lifesteal value, perhaps even as high as 100%, but in turn, the bonus damage would need to represent a higher chunk of your potential power. So a lifesteal Denathrius has relatively weak attacks, but has really high sustain, while a sword Denathrius has very powerful attacks, but doesn't last long in battle.
Unfortunately, while I have a lot of praise for the potential of this trait, I don't think the rest of the kit capitalizes on it, making it feel almost like an afterthought.
Basic Abilities (general)
The first thing I noted reading through these abilities is just how many different 'marks' Denathrius has. Burden of Sin, Touch of Night, March of the Penitent... It's just way too many different mechanics that don't actually add up to more than the sum of their parts. Put together, the moveset is very complex, but the interplay between the different abilities isn't particularly interesting. Ideally, a hero should try their best to stick to a single type of mark that informs their entire kit.
That said, I think there is something salvageable about the idea of a hero with three different 'marks'. Similar to Imperius, the approach I would take would be to make the trait read something like this:
"Each of Denathrius's basic abilities applies a mark to the enemy hero for 4 seconds. Basic attacks against marked targets refresh the duration.
- Q: Enemies marked with Q take 50 damage per second.
- W: Enemies marked with W are slowed by 20%.
- E: Enemies marked with E Have their armor reduced by 10."
From there, you could apply numerous additional talents, such as "Heroes with all 3 marks applied to them have the effects of the mark doubled." This kind of design is what could be called a 'talent playground', where the general design is very basic, but the potential for talents is incredibly high. That said, this concept and your current trait would likely be mutually exclusive, meaning you would likely want one or the other.
Q
A fairly straightforward coneshot that creates an immediate incentive for your opponent to move, or be forced to take additional damage. This is an interesting design for an ability, though it suffers from being overstuffed. Simplifying it down to "deal low damage in a cone/area/line. All enemies hit have a pustule spawn under them, which explode after X second(s), dealing high damage" is plenty interesting on its own, and forces Denathrius's opponents to always be on the move. Just like Denathrius's trait, this aspect of the kit could be used as the foundation of a moveset all its own, it just doesn't quite know when to stop.
W
Night Hunter I'm not sure what to think about. 2 seconds is probably you trying to be conservative, but lowering it down to 1 second would put the move closer towards that sweet spot of being delayed-yet-practical. This one boils down to being a skillshot with a delay at the start, and an explosion at the end. A perfectly fine poke tool, with potential for talents. The idea of it marking targets to take extra damage from the next cast isn't bad, but it's not really synergistic with the rest of the kit, nor with its delay mechanic.
E
This one is basically Malthael's warp, but on a hero that I'd argue has no real use for it given the rest of his kit. Additionally, while I talked about the marks in a previous section, I'll note that while having an ability that consumes the applied stacks is often a good coup de grace for a hero, you generally want it to be the final payoff for applying stacks, while this one's pretty negligible. If you redesigned this move as more of a 'final blow' move, it would likely fit a lot better. Also, I'll mention that an 8 second DoT is something that can lock heroes out of major aspects of their kit for an unreasonably long time for little investment from Denathrius, though that's more of a numbers thing.
R1: I'd say this is somewhat comparable to Octograb, only with Denathrius being interruptible. It runs into a lot of the same frustration factor as Octograb, but I think it'll all boil down to a lot of different factors as to whether or not it would need major adjustments. This is also another move that would benefit from being boiled down to the essentials.
R2: Fairly straightforward. Create an area of denial, but this one deals its damage in lines. I will say that your Denathrius does have somewhat of an area-denial theme, so this does fit into that.
Overall, this kit is one that has a lot of things I like in it when judging individual aspects, but as a whole, it feels like a lot of different ideas are competing with each other. The other major problem is that a lot of these abilities are too immediately complex right out of the gate. Stripping them back to their essential functionality, and putting some of the extra stuff into the talents would be ideal.
The way I see it, your Denathrius has three different identities, which are as follows:
Master of Marks (W/E) - Critically applying and maintaining different status effects.
Duke of (Area) Denial (Q/W) - Firing off moves that are easy to dodge, but constantly force your opponents to move, or to take unhealthy risks.
Baron of Blood (E/Trait) - Getting up close and personal, and regularly choosing if you want extra damage, or extra sustain.
I'd argue that you'd be best off focusing on just one, with just a bit of spice from one of the others.