Ive always had both of them together in my Darius build and felt it was great to get the 32% life steal (12 from hydra and 20 from BT)
I know it says passives with the same name dont stack but that doesnt apply to the lifesteal right?
It stacks. You can check your total on your champion stats window.
passives with the same name don't stack applies to things like Liandry's Torment (UNIQUE PASSIVE – EYES OF PAIN: +15 magic penetration) and Sorcerer's Shoes (+15 magic penetration) you will only get the 15 MP from one of these items.
Passives will stack, as long as they are not UNIQUE passives.
The 12% lifesteal on Ravenous Hydra is not a Unique Passive, it's just a stat built into the item. You can get 34% lifesteal by buying a Ravenous Hydra and a Bloodthirster.
However, since the 20% lifesteal on Bloodthirster is Unique, you couldn't get 40% lifesteal by buying two Bloodthirsters.
