I honestly think that Wizard/Cipher with Whispers of the Endless Paths is a very accurate representation of Elric. The website you pointed out is Elric as the apotheosis of the Eternal Champion. He starts out much much weaker and it takes him a lot of time and souls for him to grow into that.
In the book series (and also the roleplaying game) he spends a lot of his time having to plan his spells and conduct rituals with more powerful deities to actually wield magic. The same goes for his enemies like Theleb, Yyrkoon, and Jagreen. They all spend time casting rituals and researching spells to try and thwart Elric. Magic doesn't come easy and many are the pacts with fallen or lost beings that are made to learn and manipulate magic within the Young Kingdoms. Cipher is a perfect class mechanic to demonstrate Mournblade's powers that Elric has at his disposal including the feeding of his opponents' souls to grow his own capabilities. You won't internally have his ability to summon creatures like he does in the books, but you can supplement this with the figurine summons. It actually works better this way as summoning a creature in the Young Kingdoms requires a pact with that creature and those are not made lightly or frequently!
I'm pretty sure that Wizard is fairly soloable on POTD and so linking it with Cipher shouldn't cause too much headaches for your run.
Dejnov.
