Hello hive, this is my first trigger-based ever to create ( im new at trigger programming ) and i upload it here to get some judgment about my work

I have been visiting the hive quite a time now downloading models only and now i that i have decided to learn the powers of the triggers i give you my first work to get your thoughts about it
The spell:
Its quite an easy to do, and quite usefull as a boss ability.
The deal is this.
The caster summons 12 death knights arround him which heal him with their death coils.
Each coil heals the target for 50 hit points which makes total of 600 hit points healed.
All of the above can be changed by the user

NOTE: all the units appeared as decorations are locusted as well as the death knights dummies
Not a big deal but its a start
I hope it get aproved and i hope you give me as many thoughts and suggestions as possible
PS: remember that i am a newbie in trigger programming ;p
*UPDATE*
-Fixed leaks
Keywords:
Deaths, Healing, Grasp, Heal, Healing, Death Knight, Death Coil, Undead, Dark