Is there a way to make an ally (character) character who follows the player and fires to a specific character without using the behavior tree?
Yes, this is in 100% possible as I know, means you can use all engine functions available in Behavior Tree
But question is - why not Behavior Tree? If you have very simple ai, you can do it in it’s blueprint but doing it with Behavior Tree is much better and easier, just start with Behavior Tree and whole this system can be hard and confusing, but anyway – much harder will be do it without BT.
Here is parallel to Animation Blueprint. You not need it, but they are for a reason and really works and make work easier.
Personally I have most of ai on Behavior Tree and Tasks, Services and EQS queries.
whats wrong with BTs?
I do not know where to start
I do not know where to start and I only have time to study a prototype
Best tutorial to start with AI and behavior tree I know - shorter for a effect and very good for add custom content later is here Introduction to AI - Part 1: Behavior Tree Basics - YouTube
Just do what he doing step by step and your ideas you can add later, when you will have all working as on tutorial. It need few days to do it, but here no shorter way and this tutorial is very good base for all types of ai.