Description:
This is very simple(ish) system, but affective way of doing summons for your game using the event system. It also works with PvP but the player must be attacked (Or have met a condition you set), it also works with a criminal system I have so if a player is a criminal the summon will attack. Can set different conditions based on your game.
Video:
https://www.ascensiongamedev.com/resources/filehost/ac1bd0b14a7dd8123876ca9015247bc8.mp4
Process:
Use a spell or Item event to "Summon" your NPC Minions
Issue:
Player will not get experience when a summon kills a NPC.
PvP does not seem to be working anymore... I am investigating to find a solution.
Addon:
None
Note: Below build is for my space game, change naming of variables and such to suit your game style.
Build: 
1. First we need a two player variables as this is key to the system working correctly and have the NPC not attack the player, PVP, as well as so other players summons do not conflict:
2. Let create the NPC we want to summon. This system utilises NPC vs NPC, so as you add more NPCs to you game you will have to amend this NPC and other NPCs you add so they can attack eachover:
3. Now lets make the common event which will spawn/summon our minions:
4. Lastly we build the spell or item that you want to use to summon your minions:
Thats it...simple really using the powerful event system of intersect
Enjoy