Somewhere in the wiki, it says it is, somewhere it is not clearly mentioned.
Especially on these items. 
and 
.
Are the life steal from these items "on-hits"?
Plus would 
apply effects of life steal of the above items twice? (every other attack)
Runic Blood2 votesYou would have to have fervor of battle or Botrk to deal physical damage on your bonus sated auto attack to proc lifesteal. But yeah if you deal physical damage on your sated attack and you have life steal it heals you.
Xelnex1 votesWas asking specifically about the and items.
Thank you for your fast reply tho.
Nameless Voice1 votesNo, lifesteal itself is not an on-hit effect, though it only applies to attacks that proc on-hit effects. You will not heal twice with the Sated double-proc.
Xelnex1 votesSo what will happen if i buy and
Nameless Voice1 votesYou don't get an extra attack. You proc on-hit effects twice, but not the attack itself.
Mysticman891 votesThe two items you mention just give additional lifesteal, which affects any physical damage you do regardless of source (theres no such thing as specifically on-hit lifesteal, it's just the same ole lifesteal, you just tend to do physical damage on-hit so it counts there).
The second hit from sated devourer only applies on-hit effects (so notably doesn't do a second AA's worth of damage), so if all your on-hit effects do no damage at all (e.g. they're status effects), then there'd be no physical damage from which you could benefit from lifesteal off of. If all your on-hit effects do magic damage, again you wouldn't benefit from any lifesteal since lifesteal only affects physical damage. If any of your on-hit effects happen to apply physical damage (e.g. bork), then your lifesteal would apply to that damage.
Xelnex1 votesSo what you are saying is that, and will not give any extra life steal, just the same lifesteal you would get without a sated devourer, correct?
In a way lifesteal is not an "on-hit effect" right? unless you are using 
and 
.
And sated would not heal me if the damage dealt is magical, such as 
. correct?
But since it says it will deal an on hit effect a second time, would that mean i can get a second "shiv" attack?
Also 
deals an extra 15 on-hit damage, would that mean i get 30 total damage every other attack?
Mysticman891 votesRight, BT and DD both just give lifesteal and lifesteal-like effect respectively, with no special on-hit interaction.
gives 10% lifesteal, and as a separate effect does %health physical damage. Since it's physical damage, lifesteal applies to it. similarly gives 12% lifesteal, and separately has effects that do physical damage. Since it's physical damage, lifesteal applies, although due to the particular passive on that item it only applies with 50% effectiveness.
Shiv's passive deals magic damage, and so lifesteal wouldn't apply to that as you said.
The phantom hit from sated does count as an extra shiv stack, and will proc the runan on-hit damage a second time as well.
EndlessSorcerer1 votesSated Devourer's Phantom Hit is basically coded as a second basic attack with 0 base damage. Even if lifesteal was applied to that Phantom Hit, it wouldn't heal you.
IIRC, the only exception to this is Blade of the Ruined King, since they specifically let the damage dealt by its on-hit effect apply lifesteal.
Xelnex1 votesThat would explain a lot, thank you.
But what if you are using ? would both the passive and unique passive apply, or just one (or none) of them?
The passive is 50% of total damage dealt by that item, (which should be zero according to what you mentioned earlier) But the unique passive, that is the cleave, should apply right?
EndlessSorcerer1 votesI'm not sure since I've never tested that combination. I'd usually just get Titanic Hydra if I had built Devourer for the on-hit damage.
Xelnex1 votesI just edited the previous post. I am just trying out new combinations, etc.
Titanic hydra deals damage based on how much health you have, the other hydra deals damage on how much attack power you have, so if sated works on the titanic hydra, it should work on the other one too right?
(i know you said you havent tested it yet, but it should right? )
Sightless661 votesLifesteal is not an on-hit. It is a characteristic that heals you based off of physical damage from autoattacks and physical on-hits.