I’m not normally one to peruse the forums (as my post-count will undoubtedly show!) - but I’m all about helping folks out in finding a concept they like. So here goes.
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I’m going to have to plop down two very different answers in this case, because according to your first post, you seemed enticed by the dark armors, runic abilities and overall “death vibe” of Death Knights - but perturbed by playing an emotionless killing machine.
So… first idea from my odds-and-ends brain;
And in that case, might I suggest a concept - although highly unusual - of a living human necromancer, perhaps a warrior before some sort of situation caused them to dapple in the dark arts. One who prefers to still get in, close and heavy with armor and a giant sword to dish out their hatred, revenge, whichever. Enchanting their blades and armor with necromantic runes of Death and Shadow.
Thusly, you avoid the emotionless killing machine in favor for a living individual with a troubled past. Granted, you’d have some troubles getting into actual hubs without hiding what you dapple in; Necromancy being one of those “Big No No”'s after all.
But as for your later post regarding just well… Plate and bulky armors; second option! Let’s go!
Most definitely a thing in lore, although notoriously ‘elven’ in most cases; there in fact exist such a thing as that; Battle Mages. from groups such as; the Silver Covenant, the Sunreavers, Baradin’s Wardens, 7’th Legion, the Kirin Tor and many more. These mages are often more heavily armored than their more ranged counterparts and utilizes swords and staves (the majority).
Battle Mages, Spellblades and let’s not forget Spellbreakers! Now there are plenty of ways you could ‘say’ your character was trained, raised or had of relations that could lead them to being either of these. A neutral fellow in Dalaran for example. Friends in odd circles - the list goes on.
But you could also tread the path less traveled and find another RP’er to train your character in these things. It makes for remarkable storytelling and a wonderful narrative setting that can just really take off in all the right ways.
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So whether you go for a necromancer in bulky armor (a bit unconventional) - or the tried and true Battle Mage of the Kirin Tor - or even Runemaster - I’m going to always advocate for finding RP to entice you further onto a path you can enjoy.
Here’s a few nifty things. First of which; Spellblade Aluriel. From the Adventure Journal;
Aluriel always had an affinity for magic. She rose through the ranks of the Nightguard effortlessly, having a natural talent with the sword. But no matter how strong she became, she wanted more. She studied with the mages at the University of Suramar, spending her days in combat training and her evenings in the artificery. She forged her weapons and armor in the Nightwell, weaving magic spells into the precious metals. She is the first Spellblade, adept in the schools of Fire, Frost and Arcane.
Blood elven Spellbreakers; https://wow.gamepedia.com/Spellbreaker
Rune magic; https://wow.gamepedia.com/Rune_magic
Enchanters; https://wow.gamepedia.com/Enchanter
And now; apologies for the word-vomit, but I hope it helps. Have fun out there!