Seriously, Sion's old ult (excluding the name) fits Aatrox's theme like a glove.

Cannibalism Grants Sion 50 / 75 / 100 % lifesteal and 50% attack speed for 20 seconds. Additionally, Sion's attacks heal surrounding allies for 25 / 37.5 / 50 % of damage dealt.

Replace Aatrox's ult with Cannibalism and you'll see Aatrox truly inspire his team to keep fighting until the last drop of blood is spilt.