Idea:
* Some abilities work only at night, daytime severely limits the assassin's abilities. As game time goes by, his abilities grow in power until he can use them in daylight.
* The game keeps track of how often a particular hero is targeted by the assassin and runs a Paranoia counter. As the counter (and game time) goes up, some spells become more effective. If the counter maxes out, the hero finally becomes Neutral Hostile. The NH hero drops all items on death, and once killed a new, level 1 hero of its class can be trained. Paranoia can be lowered by killing the Assassin or other means (liquid courage?).
Stances:
Aspect of the Striking Snake: Specializes in swift attacks but leaves the Assassin open to counterattack. High damage and speed while invisible but weak and slow when discovered.
Aspect of the Waiting Spider: Specializes in traps and poisons. High mana, average combat ability.
Aspect of the Twin Mask: Specializes in manipulating emotions. More effective spells (lower cooldowns?), low combat ability.
Abilities:
Snake:
Raptor Strike (Active): Blink to target, channel for several seconds, then deals damage and blinks to starting point. If the target moves away, is not instantly killed or the assassin is detected, the attack fails and he does not blink out.
Feint (Active): Creates a mirror image of the assassin that Wind Walks towards the target and attacks, dealing no damage. Successive uses of this spell send more images (one after the other), until the assassin himself Wind Walks to the target and attacks for damage. Detection will not cause the mirror images to interrupt their attack.
Moving Shadows (Channeling, only works at night): Creates mirror images of the assassin with permanent invisibility, all moving in formation with a central clone. Invisibility is removed periodically when moving so the shadows appear and disappear and removed when attacking. The assassin may switch out with any shadows in order to attack with a Wind Walk effect, ending the spell.
Night Mother (Passive): The Assassin gains increased health and mana regeneration while invisible at night.
Haschich (Active): The Assassin targets an allied unit. That unit receives a huge attack bonus that lasts as long as it gets told to attack a target. If the target is killed or a different target is selected, or the unit makes more than three attacks, it loses the bonus and get the Dizziness debuff. If the unit's target is killed, surrounding heroes have increased Paranoia.
Surrounded by Traitors (Active, Ultimate, only available after a large amount of game time has passed and the targeted unit has a high Paranoia status): Target hero is forced to attack the closest allied unit with a big damage bonus. As the spell increases in power, the spell's duration and the attack bonus increases and the number of targets ordered to attack increases.
Spider:
Aura of Fear (Passive): While invisible and in range of enemy heroes, their Paranoia count slowly goes up.
Nightmare Fuel (Active): The target's Paranoia count steadily increases while under the effect of the potion. At higher levels it can only be dispelled by anti-paranoia effects instead of dispels.
Fear Gas (Active, AoE): All units in the AoE have their vision range and accuracy reduced, and restored once out of the cloud. Paranoia count increases as long as the unit remains in the cloud. At higher levels the cloud slowly follows an enemy hero until it dispels.
Trap (Active): Creates one of several invisible wards that target any enemy unit walking over the trap without breaking invisibility, with cooldowns lasting as long as the effects:
* Silk: Webs a nearby enemy ground unit and reduces their vision to zero.
* Pitfall: Stuns a single unit at a time.
* Volatile Poison: Puts the Disease Cloud debuff on the unit.
If a hero is hit by the wards' spell, increases Paranoia count.
Spider's Web (Ultimate, Channeling): Creates a large amount of Silk wards across terrain, slowly spreading out from the assassin's position in a web shape. Wards have detection and can web multiple units. If a unit is killed while under this effect, his corpse spawns a small invisible health powerup.
Mask:
Disguise (Active): Assassin disguises himself as the worker unit of the targeted faction and becomes neutral to them (though with their team color), allied with their allies and enemy to their enemies. When breaking disguise to attack, the disguise takes a few seconds to wear off, and the assassin's previous alliances are restored. There is no damage bonus to attack, but does not set off detectors either except at very close ranges. If attacked while disguised, the disguise wears off instantly and restores alliances.
False Messages (Active, Channeling): Targets an enemy hero. The hero's player will receive false messages about being attacked at a random point on the map (low probability of indicating the assassin's location?) or gold mines running low/out while the spell lasts.
Poisoned Drink (Active, Permanent until dispelled): Targets a hero. Gives a small chance that the next healing item used by the hero will poison him instead.
Nowhere to Hide (Active): Targets a hero, the hero becomes visible to the assassin and his allies while the effect is active. Whenever the hero becomes invisible, ethereal, uses mirror image, or goes in a transport, the hero's current location is pinged to all his enemies.
Intercepted Orders (Passive): While in range of an enemy hero, every time the hero is given an Attack-Move order to a location, the location is pinged to all players.
Apple of Discord (Active, Channeling, Ultimate): Creates an item (after channeling) at the Assassin's location that greatly increases the hero's stats and abilities but decreases those of all allied players' heroes. Item drops on death. When picked up, all allied players receive a message explaining why their heroes are suddenly weaker, and that the only way to prevent this is for the hero to drop the Apple or kill him (if dropped, the Apple does mana damage). If the assassin is killed during the channeling, the Apple becomes a Crown of Kings instead.