Can someone explain why Cisco started to fade away? That part made no sense, is it because hewas killed by reverse flash in a different timeline
Reverse Flash gave Cisco his powers. By capturing him, Cisco as we now know him today would not exist. The simplest answer I can give you. Barry, on the other hand, we know that there's an ORIGINAL timeline in where he going to become the Flash regardless that did not involve Eobard Thorne. All Eobard Thorne did as Harrison Wells was to make the chain of events happen quicker with him. That's what I gathered from it.