Earth Mage (Tanky Mage) concept
While I made the numbers specific, they are probably a bit overpowered and as a result I suggest reading this for the idea, not for the exact numbers. It's a pretty unique champion thanks to his passive and W, and I basically just kind of felt like an Earth-based mage would be pretty cool.
Earth Mage wields a hammer, but has ranged abilities, making him an excellent support or jungler. His CC is extremely strong, and his base damages are good enough for him to build quite tanky. However, he suffers from relatively long cooldowns and rather low burst damage potential. Regardless, his damage can very quickly add up and his dueling power is quite strong, especially in combination with his Earth Doll which can block enemy skillshots for himself or an ally. He is the worst nightmare of champions with channeled abilities like Katarina and Nunu due to his Earthquake ability and large number of stuns. However, once it has been used it will remain on cooldown for most of the fight.
He could also be a very nice AoE burst mage, assuming he hits all of his spells on a lot of targets. I believe that he would be best as a support or jungler but he could be played mid or top as well against some matchups.
Passive - Earth Doll(The Block?): Earth Mage commands an earthen doll with alt+right click. This doll can move up to 2000 units from Earth Mage before being teleported back to him, and cannot attack. Earth Doll’s primary function is to tank skillshots and grant vision. Earth Doll has (100/300/500 +20% of Earth Mage’s max HP), and regenerates health at a rate of 3% per second. Once Earth Doll dies, it automatically respawns at half hp after 120 seconds. It should be noted that Earth Doll has a very short vision range.
Q - Boulderdash: Earth Mage causes two boulders to rise up from the ground (a short distance apart from eachother) at target location. After 3 seconds or on second cast, these boulders are dropped, causing (90/155/210/275/340 +40% AP) magic damage to enemies that are hit by the spell. A 0.3 second stun is also applied. Enemies cannot hit by more than one boulder at a time.
Range: 750 units AoE Radius: 275 units (per boulder) Mana Cost: 85/90/95/100/105 Cooldown: 11 seconds
W - Earthquake: Target area begins to shake violently for 3 seconds, throwing nearby enemy units toward its center by (10/15/20/25/30) units every second. Enemies in this area also take (2/2.5/3/3.5/4)% of their max health as magic damage each second. In addition, these enemies take (30/55/80/105/130 +30% AP) magic damage per second while standing in the area.
Range: 845 units AoE Radius: 275 units Mana Cost: 105/110/115/120/125 Cooldown: 11.5 seconds
E - Sharp Plating
Passive: Earth Mage permanently gains (10/15/20/25/30) armor and magic resist and returns 8% of physical damage taken back to the attacker. Active: For 4 seconds, Earth Mage is enveloped in earthen spikes. Upon suffering physical damage from an enemy, the attacker receives (22/32/42/52/62 +20% AP damage per second for 2 seconds. Enemies that autoattack Earth Mage while affected by this debuff are stunned for 0.6 seconds.
Range: 445 units (The stun and damage from the active can only take place within this range) Mana Cost: 30/40/50/60/70 Cooldown: 15/13/11/9/7 seconds
R - Earthen Explosion: The ground beneath target enemy champion instantly erupts into a violent explosion, dealing (125/200/275 +55% AP) magic damage to all enemies caught in the blast and stunning them for 1.25 seconds. After the stun ends, the damaged enemies incur a loss of 25/50/75 AD and 10/20/30% Attack Speed for 2.5 seconds. Additionally, for 3 seconds after the spell is cast, all of Earth Mage’s spells deal an extra 15/22.5/30% damage to all targets that were hit by Earthen Explosion.
Range: 350 units AoE Radius: 400 units Mana Cost: 100 mana Cooldown: 120/110/100 seconds