I think Durin VII is just the descendant of Thorin Stonehelm, not his son. (The line isn't permanent) But the idea and the linked picture isn't bad.
It seems, in the end, the most canonical way to reintroduce the myth of Durin.
I myself proposed a possible way to introduce the forefather and greater of all Durin I the deathless (through both his original body and spirit), but it is a intricate road.
Making further researches i discovered theme of reincarnation seems the most canonical to construct a solid lore basement. Tolkien mention that the Dwarves buried Durin I in Moria, but they consider him as in a "longeval sleep" rather than really dead.
His spirit rests with his body awaiting for day would ultimately awake.
Focusing on this last point : it could be more logical to interpret his "awakening" as a spiritual reincarnation , rather than his original body walking in middle earth again. A real resurrection of is body from its coffin would appear less canonical i supposed, since those type of so to say "necromancy stuff" is usually associated with evil (Sauron).
But anyhow we are discussing about the first Forefather, not a random king of the dwarves. He was made directly from the hands of Aulë so also a real resurrection (spirit and body) could be possible in some magical way (maybe through the blessing of Mahal himself
). It is a very complex field in my opinion
At least, with respect to other great heroes of the past, he's the only one (if someone is more learned correct me) of which we have clear references of his possible return (independently of what way is considered more lore-accurate).
Anyway, returnig on our primal idea : there's no detailed info about Durin VII, except he's the Last king of the dwarves, and he definely reclaims Moria. We have to add some elements imo, as canonical as possible (Blue just started the process introducing the timeline of his birth).
So, stating that:
- he's the son/heir of Thorin III.
- he was (probably) born before the war of the ring and the death of Dain II.
How to connect him suitably with his grandfather and the theme of refusal of the ring?
Two brief scenario to start the development:
Scenario 1: Dain gives up the ring to his grandson, which he's recognized as the true reincarnation of Durin I. He's so the only one who can use it in a proper way, without being corrupted by its evil influence. With the one ring his spirit is further strengthen, awakening totally the original power of his ancestor.
In this concept there's no a total detachment from the evil artefact, because is used anyway.
However, like Gandalf the white, the evil power of the One is used to do good.
In game: when you activate the refusal option, Durin VII is summoned near Dain, and if he dies the ring is dropped.
Scenario 2: Dain totally recject the One, because he doesn't want to help his proud people using the weapon of the enemy, it can only leads the dwarves to destruction.
Dain passes the ring test and the dwarves folk is blessed by his maker Aulë : the smith of the Valar send a gift to his creatures, totally restoring the ancient might (sorry DieWalküre if i breaked the copyright rules on your invention
) of Durin through the last true heir Durin VII.
In game: when you activate the refusal option, Dain VII is unlocked as a recrutable hero in the citadel, at a cost of 3000.
The ring is totally unused (as Blessed Galadriel case) and if Durin VII dies the ring isn't dropped.
What is the best 1 or 2 in your opinion? I'm still thinking about the abilties of Durin VII. If make them almost identical to Durin I or change some of them.