People will think you're trolling with this build especially if you begin with 4 daggers (which you'll need to build every item).

This kayle can 1v1 or flash into the middle of the entire enemy team after they have been initiated by someone other than yourself.
- Cast Q/Flash into the middle of the fight or towards the enemy and then Q
- Cast E for range
- Ignite someone
- Allow your attack speed to max out the magic/armor shred
- Heal yourself if needed
-If you can wait to ULT yourself then do so but if not, do it immediately after the heal
By doing these steps, your splash damage would have reduce the entire enemy team's armor and magic resist allowing yourself or whoever else in your team is alive to finish them off.

There are 3 alternate builds with only the final item being different.
Use the one with ___________ to:
Nashor's tooth - Endless Q+Attack Speed
Gunblade - AP+AD+lifesteal+nuke
Guardian Angel - Deal damage, shred, ult, die, heal and second chance at killing everyone who's running away and can be chased with flash, W, Q, E, ignite.

Magic and Armor Def + 25 Armor Pen, Alternatively you can use MPen instead of APen if you want to surprise them with magic damage if the enemy decides to go heavy armor.
9 Marks of Desolation
9 Seals of Resilience
9 Glyphs of Warding
3 Quints of Desolation

Ignite and flash

Last hit your best with E or harass squishies with E

Focus on maxing your E asap, but if heal is needed then alternate between E and W while still prioritizing E.