Rivviere and Deneb, The Star Eaters
Deneb is one of the ancient demons, one which only a distinct few can summon. He carries out tasks in a brutal fashion, choosing to devour his victims while they are still alive. He has huge arms with claws, glowing white eyes, and his stomach area is lit up by 3 dim lights, which are said to have once belonged to Aurelion Sol. He is currently under the control of a powerful Noxian mage called Rivviere.
Passive - Contract with the Star Eater "We are bound by this contract. We will stay together until this mortal body gives in." Casting spells and killing enemies generates Summoning Mana. Having 100 Summoning Mana grants you 10% movement speed. When out of combat for 6 seconds, you lose all of your Summoning Mana. Q - Claws Of The Beast "Time for me to have some FUN!" Empower your next basic attack, making it deal bonus damage equal to 20/25/30/35/40% of your Ability Power. Generates 50 Summoning Mana. Casting this ability while you have 50 or more Summoning Mana expends all of that Summoning Mana and instead Summons the hand of Deneb in a nearby area to slash at all enemies, dealing 80/100/120/140/160 (+60% AP) damage. W - Spell Block "NOPE! ... Nice try though." Raise your spellbook and create a small barrier spell lasting for 1.5/2/2.5/3/3.5 seconds, reducing all damage that you would take for that duration by 25/30/35/40/45%. Every spell which you reduce the damage of with this spell grants you 30 Summoning Mana. If you have 60 or more Summoning Mana while casting this spell, you lose all of your Summoning Mana and instead of reducing the damage of attacks and spells aimed at you, this spell blocks those attacks. E - Contract Breaching "Lucky for you, breaking rules is my specialty." Expend all of your Summoning Mana. You cannot generate Summoning Mana for the next 12 seconds. You gain 5% movement speed, and 20/25/30/35/40% of your Ability Power is turned into Attack Damage. You can move through units, and your Attack Range is increased by 100 for the duration. R - Summon : Deneb "I will ... DEVOUR them!" You can only cast this ability if you have 100 Summoning Mana. You lose all of your Summoning Mana. After channeling for 1 second, Deneb emerges behind you and rams at the nearest enemy champion, dealing 150/200/250 (+50% AP) damage to them. Deneb remains summoned for 1 minute, and has stats equal to Half of your health as health and half of your Ability Power as attack damage. If Deneb attacks an enemy with his basic attack, that enemy takes 50% reduced damage from him for 5 seconds.