Hero concepts

Infernus, the Fire Lord

[STR] 22 + 3.3
AGI 16 + 2.4
INT 19 + 2.5

DMG - 52
Armor - 2
HP Regen - 4

Movement Speed -280
Attack Speed - 90

Lava Pool (Cooldown 20/18/16/14)
Mana cost 110/130/150/175
Pierce’s spell immunity: No
Dispellable: No
Damage type: Magic

Creates a pool of raging lava that deals damage over time, slows enemies and decreases their armor. DPS and effects ramp up the longer the opponent stays in the pool.
If 4 seconds are sustained in the pool, the opponent is silenced.

Max DPS 25/40/65/80
Max slow: 15%/30%/45%/65%
Max armor decrease: 3/7/10/14
Duration of pool: 7

Magma Attacks (Cooldown 1)
Mana cost 30
Pierce’s spell immunity: No
Dispellable: Any
Damage type: Magic

Adds volatile magma to Infernus’ base attack that deals bonus magic damage based on Infernus’ strength and reduces magic resistance with each attack. Debuff stacks and the duration is refreshed with each attack.

Bonus Damage Strength Multiplier: 40%
Magic Resistance removal: 4%/6%/8%/10%
Debuff Duration: 5

Flame Siphon (Cooldown 30/38/36/33)
Mana cost: 100/120/140/160
Pierces spell immunity: No
Dispellable: Strong Dispels Only
Damage type: Magic

Siphons life energy from enemy heroes in an area. Once the siphon returns, it temporarily
increases Infernus’ HP regeneration based on the amount of heroes that were affected. Affected enemy heroes get burned based on their current HP.

HP Regen per hero hit: 4/6/8/10
HP Regen per illusions hit: 1/2/3/4
Base duration of HP Regen: 5
Added duration per hero hit: 1.5
Added duration per illusion hit: 0.5

DPS based on current HP: 5%/10%/15%/20%
Base duration of burn: 8
Added duration per hero hit: 1

Inferno (Cooldown 120/100/80)
Mana cost: 150/200/250
Pierces spell immunity: No
Dispellable: No
Damage type: Magic

Infernus’ crown burns with extreme energy, melting nearby enemy units for massive damage and decreasing their status resistance and their max HP. Infernus takes 50% of the damage and is also affected by the debuffs. While active, Infernus takes 25% more magic damage.

Damage per second: 100
Status resistance removal: 25%/50%/75%
Max HP removal per second: 5%
Debuff duration: 8
Burn duration: 4.5/5.5/6.5
Radius: 800

Upgradeable by Aghanim’s Scepter
Decreases Cooldown (100/80/60)
Casts current level Inferno upon Infernus’ death, which lingers for 4 seconds around the death point. Death Inferno Radius is increased to 1000

Talent Tree
Level 25-
Inferno Pierces Spell Immunity/Lava Pool mutes after 4 seconds
Level 20-
Magma Attacks bounce twice/+7 Flame Siphon HP regen
Level 15-
+Magma Attacks no Cooldown/+3 seconds Lava Pool duration
Level 10-
+4 mana regen/+30 attack speed

General build idea
Max Magma Attacks first for easier CS in lane and harass. Should learn at level 2
Get  Flame Siphon first and then max it second for survivability in lane and harass. Will help with getting bounties.
Lava Pool should be maxed last, maybe 1 level of it at level 8 because it is an area of effect zoning ability with not much potential in lane.
Learning Inferno can be delayed as you can die from it very easily in the early levels, but learning it at level 6 will also enable potential for killing a lot.

Phase Boots for chasing down enemies with Magma Attacks and staying on top of enemies with Inferno
Power Treads for sustainability
Arcane Boots if playing support

Early game items:
Soul Ring, 2-3 bracers, Hand of Midas, Veil of Discord

Core items:
Black King Bar, Radiance, Shiva’s Guard

Situational items:
Blink Dagger, Dragon Lance, Yasha/Manta Style Orchid Malevolence, Rod of Atos, Aghanim’s Scepter, Mask of Madness

 Extension:
Ethereal Blade, Heart of Tarrasque, Bloodthorn, Scythe of Vyse, Octarine Core, Eye of Skadi, Hurricane Pike, Satanic