Here is a little feedback on the small (problems) encountered on Tanking and DPS (Auto Attack)
On the first 2 images you can see the Tanking and DPS between the Chthonic Form and the Pet Necro.
Bonus :
Chthonic Form :
Pet Necro Abomination :
Summary: The Necro Pet tanks better and does more damage than the Chthonic Form.
Here you can see the difference between the Chthonic Form and Decrepit Form ( same SC / Template )
Decrepit Form :
Chthonic form :
Résumé : Decrepit Form finish fight FULL LIFE ! / Chthonic Form die Fast