in syndra creative design ama, it said that syndra hates lux for stealing other people's magic!
and her power is strong enough to break off relationship with summoners if she wants to.
but she doesn't come across as someone who would fight other mages..
she's all about freely studying magic ! sympathizing someone like xerath and being curious of powers he acquired, and wanting to see how powerful Annie will become once she grows up...etc(From ama Thread)

syndra was locked up because of how much power she has and literally left ionia with her floating castle lol

lux is very talented mage who began training early and can reverse engineer spells and control light..

i think syndra will win based on lore...i mean based on lore syndra is like on the same level with xerath..

Well perhaps if Syndra hadn't been so reckless, she might of had her chance at learning control and ultimately be more powerful. I have no sympathy for her.

I honestly feel like if Syndra were to learn about Lux's past - that she was forced into military service by her parents and her government - that she would not only empathize with the girl, but would also encourage her to break free of Demacia and live her own life. I don't know that Syndra would invite Lux to stay with her, but at the very least she would certainly feel a kinship with her. Lux is what Syndra would have become if she hadn't have killed the old man.

I disagree. To me, Syndra was being taught control, not quite the same as being controlled to the same extent as Lux.