Best enemy to farm for Embers.
Lothric Castle bonfire, just fight the one close to the bonfire and repeat.
You can one-shot these enemies on SL1 with a backstab that deals 1100+ dmg.

Things you need:
— Deep Dagger +10
— Hornet Ring
— Dark Clutch Ring

Note, to guarantee an easy backstab just run up to the top of the stairs to aggro him and let him run towards you.
If he does the thrust, quickstep or roll, easy backstab.
If he does a horizontal attack, quickstep once and only once, tank the 2nd hit of that combo while you move around him to get the backstab. If you roll or quickstep to avoid eating the combo, you'll be too far away for the backstab.

After you have a bunch of embers, make a backup of your save file before you start grinding away at whatever boss you're on. Reload it once you run out. Much faster than farming again.
Good luck.

These have an almost identical move set to the Leyndell Knights in ER but these are much faster. diagonal slash > horizon slash > thrust. shield bash > thrust. these enemies are very easy to get behind and backstab since they lack wind up attacks and no lightning strike AOW.

Used to hate these guys due to their insane aggression, infinite stamina and practically non-stop attacking... Until I started using the Fume Ultra Greatsword, much easier to deal with when you can make pancakes out of their stupid infinite stamina having asses