Enhanced Undead are seemingly genetic experiments created by Lord Aldia, in his attempts to achieve immortality and recreate dragons. The former undead has undergone a hideous mutation which made it almost half-dragon, granting them increased strength but grotesquely altering their appearance into inhuman beasts that now prowl the darkest places of Drangleic.
The Undead's attacks drain a lot of stamina so it is advisable to evade their attacks, rather than trying to block them. They move very slowly but caution is advised, they can perform a powerful lunge attack from a distance. Ranged attacks and spells are the safest way to eliminate them but it is possible to backstab them as long as the player steers clear of their tail swipes. Using Poison Arrows is also a very good idea as they have no ranged protection or attacks.
The Enhanced Undead can be backstabbed. In particular, when approaching the player, it will almost always close the gap with a lunge attack. The player can very easily evade this attack with a sideways roll (preferably to the left) even in deep water. This will leave the Enhanced Undead's back wide open. While the backstab itself might not be enough to kill the Undead, it can easily be finished off while it is recovering (and vulnerable).
In Sinner's Rise, the Enhanced Undead to the right will be partially unaware to the player's presence. It will face back and forth between the two opening. Wait until it looks the other way to close in and land a backstab.
The Enhanced Undead can also be killed by repeatedly baiting its left handed swipe attack and landing a single blow while it recovers. While in close quarters the Enhanced Undead will use this move frequently so the player should be able to kill it fairly quickly. It is strongly advised to completely avoid its tail swipe attack however, it deals a lot of damage and has a deceptively short recovery time.