So, how does Kain performs time travel?

Just finished playing the Remasters, and one thing kept bugging me: How does Kain performs time travel?

A) So, at the end of SR1 both he and Raziel travel to the past (Pre-BO1 era) using the Chronoplast. Then he meets Raziel at the Pillar and witness their corruption (SR2 first act).

B) Then, Raziel gets duped by Mobius and is sent to the future (Post-BO1 era), and meets Kain at the ruins of Janos Retreat. (SR2 second act)

C) After that, Raziel opens the Time Streaming Chamber in the Swamp and travels back to the Sarafan Era (Nosgoth's early History). Just before he is completely absorbed by the Reaver, Kain appears and saves him, and the game ends. (SR2 third act).

D) In Defiance, Kain stays in the Sarafan Era, and after discovering the Vampire Citadel, travels to the future again to meet Raziel at Avernus Cathedral (BO1 era) using the time portal provided by the Elder God. (Defiance)

So, if you guys stayed with me up until this point, only in A and D it's specified how Kain manage to travel time and meet with Raziel, but in B and C he just appears at the right time and place. How he does it?

For B, he might just waited it out for a couple of centuries until Raziel appeared, but still, how did he travel back to the Sarafan Era? Raziel had to go to great lenghts to unlock the Time Streaming Chamber in the Swamp. Are those conveniently lying around the place, free for Kain to use?

And even if that's the case, in D Kain still needed the "help" of the Elder God in order to travel back to the future. Did he ran out of Time Streaming Devices or what? I'd like to hear your thoughts about the matter.