The Design Process
I started Twisted Cleric with the aim of creating an Intelligence pusher that could both jungle and take the long solo lane, by means of an ability which killed a neutral/enemy creep or denied a friendly creep.
The first step - designing that ability - also ended up being the hardest:
My first take on his creep-killing ability involved healing a percentage of the health of target creep in an AoE, but I discarded that after deciding it had too much in common with Parasite's heal from creeps.
I considered instead an AoE nuke that dealt a percentage of the health of target unit in damage, but the ability would be overpowered on Ophelia's creeps while underpowered on the smaller jungle camps . I changed the damage from hp-based to fixed values to alleviate some of that, but the hero still had too much early ganking potential when combined with minions.
After trying out a few ideas to reduce this early ganking power (such as leaving a DoT in place of the creep instead of dealing burst damage), I ended up with Detonate in its current form.
Originally I actually had Twisted Cleric as melee hero for easier jungling with a hatchet/shield, but ended up changing him to range along the way in order to give him a bit more of a lane presence.
I worked on his next two abilities at the same time as his first, with the intention of giving him some pushing power:
When I had Detonate down as a percent-of-HP-based AoE I considered as for this slot an ability Empowerment, which both increased the hit points of a friendly creep and gave it an aura (so it was useful both with Detonate and for pushing).
The creep's aura was originally an attack/movement speed buff to allies, but when I decided I wanted that aura in his 3rd ability it was changed to an armor debuff.
When I changed the hero from melee to ranged and Detonate was still a DoT effect, I realised the hero could do with a summon both to take damage from jungle creeps while they stood in the DoT and as an extra target to Detonate.
To stop this summon from being too strong a jungling power, I decided on the corpse mechanic and gave it low damage. The armor aura carried over, and so Empowerment became Vile Construct.
I wanted an attack speed/movement speed aura buff somewhere on my Dream Team.
When Twisted Cleric was still melee and Vile Construct was still Empowerment, he needed a little something to improve his jungling ability. Seeing as it also helped his pushing ability, the attack speed/movement speed aura fit him nicely.
Upon Twisted Cleric being changed to a ranged hero the aura remained, though it was later altered to scale between the two buffs.
I don't remember how I came up with the mechanic, but the scaling between movement and attack speed appealed to me so much I decided to implement a situationally scaling ability on each member of the Dream Team.
The first 3 abilities done, I started on the Ultimate ability. I wanted an AoE damage ability that would be useful in team-fights, and I wanted it to give Twisted Cleric some offensive potential when combined with Vile Construct and Detonate.
I ruled out AoE stuns and immobilises as ways of getting a Vile Construct to Detonate on a hero, because Tempest and Keeper already cover those abilities respectively and I don't want to fill too similar a role.
I initially played around with an AoE effect like Puppeteer's Hold which stopped enemy heroes from moving away from Twisted Cleric, but there were too many messy elements involved with that and I ended up switching to the current effect: a strong AoE slow.
I'm really happy with how Twisted Cleric turned out - designing a hero for this role was an enjoyable challenge.
Any feedback is welcome, though I would prefer if you focused on the mechanics and concept rather than numbers.
Next up, the rest of the team!