(3) How do Merlin - Who I think should keep a striped towel around his neck, often mistake for a scarf Wink - and Adrian Eldrich relate to each other?
Adrian Eldrich is still Earth's Master Mage on Merged Earth. However, Merlin is certainly Adrian's greatest rival for the title and many speculate that he could take it if he wished. What few realize is that Merlin was probably responsible for Adrian gaining the position in the first place and was a previous holder of it on Merged Earth. In the merged Earth, Merlin almost certainly gave the younger Adrian the clues necessary to find the tomb, after tracking down the ancient mage's reincarnation.
In truth, Merlin and he HAVE fought on several occasions, with Adrian winning 4 battles out of 3 because of his superior determination to win and combat skill as much as greater grasp of the mystical arts. Merlin lacks Adrian's devotion to justice and is too concerned about his own life to really want to throw down to the degree that the self-sacrificing Eldrich is willing to. Unfortunately - for Eldrich - Merlin is also a man whose mind functions on levels few could conceive of and if the archmage was ever serious then Adrian would have probably lost the battle before they fought.
On Adrian's part, he considers Merlin to be pretty much emblematic of what Archmages should not be. Merlin is an interfering busybody who considers himself above the mortals of the universe and that it is his place to manipulate them like pawns when necessary. He's also quite certain that Merlin is no longer all there and truly irresponsible with the magic he does wield (quite accurate). Plenty of archmages have gone more than a little "coco for cuckoo puffs" as Merlin describes himself, from too much power and Merlin is a borderline case.
Merlin, on the other hand, considers this to be a case of "pot, kettle, black." Eldrich has certainly played the omnipotent meddler on numerous occasions himself. Merlin believes that Adrian is setting himself up for a fall by divorcing himself from humanity and living in his sanctum where it's still the 1920s. As Merlin would point out, Eldrich probably has no idea who the Beatles are, let alone Douglas Adams (Merlin's favourite author). Merlin believes that while he may treat people like pawns, he at least walks amongst humans like an equal. That's something Adrian doesn't and which will cost him in the coming centuries.
I leave it up to readers who they think is correct.
In general, Adrian is willing to leave Merlin alone because of the fact that he is an enemy of the Inferno and the Entropic Masters. Merlin will continue to defend the Earth Realm, in part because "all of my stuff is there” and Adrian doesn't have anyone who could pick up the man's slack. He neither trusts nor likes the old master though.
Merlin, on the other hand, believes Adrian works very well as a tool to help undermine the power of beings like Una, Malador and the various powerful sorcerers in the Multiverse. Merlin could honestly care less about Medea's war against the Y chromosome or the pettiness of someone like Hell Queen that Eldrich deals with and actually dismisses their danger. Merlin deals with what he believes to be cosmic threats and alien forces rather than "Human evils, which are, simply put, human. Whether they deal with magic or not."
So, you can tell this is not the start of a beautiful friendship.