We've all had fun with our share of gimmicky decks. Whether it's that four-card combo you're dying to pull off just once, or a weird version of another deck (Temur Twiddle Storm for me), experimentation with fun and strong build-around-me cards in Modern is a staple of exploring the format.
Zur the Enchanter certainly qualifies as that. A weird card from the much-maligned Coldsnap, the odd wizard requires you to contort your deck around him in a very specific way. Luckily, there are plenty of powerful enchantments at three mana or less, and with Zur the Enchanter tying the deck together you have a huge toolbox of options available if you ever get to attack with Zur the Enchanter himself.
Of course, therein lies the problem. In the past, Zur the Enchanter decks lacked cohesion and focus. What I mean by that is players start at the top: they put four Zur the Enchanter into their deck and then start jamming it full of sweet enchantments they want to put into play with him. While this is a lot of fun and not a bad way start building the deck, what I see happen with those builds is that they feature an array of strong cards and silver bullets that are great in specific situations, but overall lack a strong core game plan outside of "hopefully attack with Zur the Enchanter."
I went digging deeper on Zur the Enchanter and I came upon a deck that has popped up over the years and, I believe, pushes the archetype into competitive status.
Like Zur the Enchanter, Doran, the Siege Tower is a card to build around, and while separate decks built around both creatures have their weaknesses exposed, together they not only fill in the gaps from the other, but they work well together.
Doran, the Siege Tower makes the mana dorks you use to cast Zur the Enchanter better. He makes the Courser of Kruphix you fetch up with Zur the Enchanter better. He's a huge beater by himself; turn-two Doran, the Siege Tower is no joke in a field of Lightning Bolt. He makes your Spellskite into a real threat and not just a deflector shield. Doran, the Siege Tower even makes Tarmogoyf better — not that it needed any help.
Fill the typical Doran the Siege Tower pieces around him and put in a robust Zur the Enchanter package, and you have a deck that functions smoothly at every axis and harnesses the power of both creatures to create a deck that is more than the sum of its parts. I've had a ton of success with this deck over the past few weeks on Magic Online — it's a blast to play and you'll definitely enjoy the look of surprise your opponents will have when you follow up Doran, the Siege Tower with Zur the Enchanter.