Heavy magicka nightblade builds are only a few out there. But 2h is pretty trendy on magicka nightbladed atm, because it grants a skill to remove snares and get immunity against it. Basically you can look out for 2h magblade builds like the one from blobsky for example and craft the shacklebreaker set in heavy (if he uses shacklebreaker). For the lifestealing part: magblades have a very strong spammable called strife. Its a ranged single target attack, which restores health for you. Similar is the skill sap essence: its aoe damage and heals you even more, when you hit several enemies. Sap essence is nice for bomblades or groupplay magblades, while solo its meh.... strife as said is vedy strong, but with a 2h you are rather melee skilled and therefore the hidden blade skill would be much stronger (but doesnt heal you).

Can it be done? Sure. Should it be done? Hmmmmmmm. Lol.

Magblades definitely excel at life steals. That’s their core spammable skill, so you’re good there. But a list of life stealy sort of powers (M=for magic toons, S=for stamina toons)

Nightblade class skills
Impale. Not really a life suck, but it’s a spectral blade that executes, so kinda life sucky. M,S
Mark target: does no damage itself, but when they die you capture a big heal from them. M,S
Soul Tether (ultimate) M mostly
Strife: the suckiest ability of all. This one sucks a lot. M
Siphoning or Leeching attacks M, S
Some others are kinda life stealing, if you use your imagination. But these are the soul suck ones...and they’re all solid skills.

Others: resto staff, force siphon. For a stamblade, a lot of the dual wield skills heal a portion of the damage done. But it’s not quite the soul suck effect you’re looking for.

You can use a 2h...but there are drawbacks. The game now lean toward having you do a lot of light and heavy attacks. Using a physical weapon on a magic character will really cost you. I mean...you’re talking 300 damage vs 6,000 per hit. But can you play 95% of the PvE content just fine with a 2h? Sure. You could use a 2h and then destro staff, I guess...I can see making this work fine.

Heavy armor can also hold you back. Light armor offers massive power buffs. A magblade is really about avoiding hits with stealth and evasion, somthey usually go light armor for the power. My advice? The outfit system now lets you skin your character however you like regardless what they’re actually wearing. So you can wear the gear that makes you most powerful (which is probably 5+ light), then go create an outfit that is the heavy look you want. Ta-da, best of both worlds.

Of course, you can make it a stamblade and then the 2h and heavy is just fine. But stamblades don’t really use the core life sucking powers...again you’d end up with like 500 damage versus 9,000 on their stam abilities.

Race: if going magic, dark elf, altmer, Breton. I like the idea of an argonian here...their healing buff would be awesome for your build idea.

Stamina, redguard, Khajiit, wood elf. I’m not sure about imperial because they’re such melee health tanks. The skills you’re leaning toward don’t lend themselves to the imperial passives.

Build

So let’s build this #&@&# magblade

Front bar: 2h (or destro): swallow soul, impale, Mark target, concealed weapon, 5th slot open (lotus fan, merciless resolve). Ultimate - soul harvest.
Back bar: destro or resto. Siphoning attacks, harness Magicka or shadow image or twisting path, crippling grasp, cloak, 5th slot open for weapon skill. Ultimate - soul tether*

*the destro ultimate is way more fun and powerful and will rain DOT death on everyone. But soul tether fits with your theme.

Gear: 5 piece Julianos, 5 amber plasm (or magic set of choice). 2 piece monster set (valkyn, gorthdarr are best. For the soul,suck theme, check out earthgore, chokethorn, scourge harvester). Note - in Summerset, 2h weapon’s count as two slots, so you can do a 5/5/2 after it drops.

Armor weight: light, with up to two heavy. Like I said, use the gear for the right buffs, then use the outfit system for the look you want. You can skin him heavy armor). Traits: divines. Weapons traits: precise, sharp or nirn on front, infused on back.

How would this play as a vet character?

This would be a dark, stealthy knight character that could deal great damage. He’d have massive health restore from the heals. He’d have good ranged and melee abilities. Soul harvest on the front bar means he’d be pulling his ultimate like every thirty seconds, so the soul harvest would be available a LOT. He might want to get cloak and concealed weapon on the same bar...they boost speed when slotted together. The 2h won’t put out much damage with light/heavy attacks, so you really want to move to the back bar when you need resources.

He’d play 98% of the game’s PvE content really, really well. I could see soloing most content with this, and it’d be really fun. In PvP this build would be a little better in a group. It might be tough to get solo gank kills. But I run a stamblade, and I’d totally take this magblade along as a gank duo...any class would because you could put out huge heals and damage at the same time.