how does penetration work in Smite?

Nope. TB gives all of your attacks and abilities 33% penetration. The way it works, is that if you have 50 flat pen and 33% pen, the enemy's protections will have 33% negated first before applying the flat pen. Remember, Percentage Reduction > Flat Reduction > Percentage Penetration > Flat Penetration.

And no, its not a buff, its a simple stat. Also, I checked personally and with my source, and my first statement is still correct: Titan's Bane and The Executioner's effects clash, because the latter makes the former less efficient.

You don't have to take my word for it. Go test it in practice jungle. The Ra bot at level 20 has exactly 60 protections. Buy the Titan's Bane on Anhur, who has flat reduction on his passive. Anhur also has exactly 90 base power at level 20, + 30 from Titan's Bane, giving him exactly 120 physical power at level 20 with just the Titan's Bane.

If you are correct, and reduction has no disharmonious effect on Titan's Bane, then Ra should be treated as if he had 40 protections on the first hit, then -15 from Enfeeble making it 25 protections. That means Anhur's base damage of 120 will be multiplied by 100/(100 + 25), or 96 damage on the second basic attack.

If I am correct, then the 15 reduction takes priority over Titan's Bane, giving him 45 protections before being affected by Titan's Bane, making it a effective 30 protections. This means Anhur's base damage of 120 will be multiplied by 100/(100 + 30), or 92.308 damage.

I will list my source: The Word of Thoth, A Smite Mechanics Guide

Edit: How on earth could you think TB only applied to basic attacks? Or that it is a buff? You don't call the 15 pen from Warrior Tabi a buff, do you?

The wording on Titan's Bane's description really needs to be changed to better convey that it provides 33% penetration against an enemy, rather than increasing your penetration by 33%.

If we're reading the same tooltip, it clearly reads "All of your physical attacks gain 33% physical penetration."

I interpreted that as basics. Somehow.

guess if xba has titan's bane and uses poison darts which hits 3 people then all shall be affected by the penetration it wont be limited to one god or your basic attack.

I think the problem was with HiRez realizing that it didn't have a passive and hastily trying to fill in the gap.

For some reason, they hated the idea of an item not having a passive effect, or at least back in the old days. I guess with the existence of Malice, there will be a lot more items with no passives.

Titan's Bane is the best pen item for gods like Hercules or Tyr who have good burst area ability damage. It's also good for assassins who rely on abilities like Fenrir or Thanatos.

The Executioner has the problem of being single-target and having to initiate with your basic attacks. I'd only recommend it with Odin, Vamana, and maybe Chaac or Sun Wukong, since they have negative swing chains.

no I would never use titan's bane on xba just wanted to know wats the truth, is it limited to basic attack or all physical abilities. Does it add to ur 50 penetration as u said first 33% is applied then 50 flat which takes penetration how much above 50?

Its actually quite simple you just shove it in!

Titan's Bane is actually quite good on Xbalanque. His basic attack damage is so high that you have a lot of room to stack pen, which makes him incredibly strong late game for shredding bruisers and tanks, which heavily cripples the enemy team.

Titan's Bane is best for gods who deal a lot of none basic attack dsmage, or even a medium amount on non-basic damage.

The only gods who I will even consider using The Executioner on are Apollo and Artemis, and literally no one else.

The upside to The Executioner is that it's an incredibly cheap item and can be built early game to slaughter tanks. I think you severely underestimate it's early game potential. But, yeah, you'd usually sell it off later for something else that makes more sense.