If you can afford this shit show of a deck, then prepare for the most glorious climb to legend yet.

This deck has a few win conditions to take advantage of depending on the matchup. Cards like Zephyrs the Great may have to be played as tempo, for controlling the board, or as a value package depending on how you intend to win the game. IT IS VERY IMPORTANT TO FIGURE OUT YOUR WIN CONDITION BEFORE YOU PLAY ANY HIGHLANDER CARDS.

Here are the main win conditions of the deck:

 C'thun OTK: against most control decks, this will be your only out. Control decks these days seem to have endless resources and even a deck filled with legendary cards can't compete with that kind of value. The main game-plan here is to draw lots of cards. Malygos, Jepetto, and Taelan Fordring are your best friends for getting to an early C'thun. Taelan is especially nice since he will either draw you C'thun if you've already completed him, or draw you Malygos which speeds the C'thun process up. While you wait for your win condition to un-shatter itself, focus on controlling the board. Siamat, Soul Mirror,  and Natalie Seline, are the perfect control tools to remove threats and keep you in the game. Finally, keep aware of the board state so that a clogged board doesn't spoil C'thun's fun.

Value Queen: One of your most powerful resources in your deck is Dragon Queen Alexstraza. many opponents don't have the necessary tools to answer flooded boards of large minions. Being an all legendary deck, one of the main advantages you hold over your opponent is the ability to keep the value coming. Besides the dragon queen; Zephyrs, Kazakus, SN1P SN4P,  and Reliquary Prime provide plenty enough of value against decks that can't handle it. However, the best way to leech value out of your biggest guns is through your support options: Bran Thaurissan, and Zola. By doubling your battlecries, reducing your costs, and copying your biggest value generators back to your hand, you can seal out most games.

Tempo Legendries: This strategy is surprisingly effective. The early game effectiveness of Serena Bloodfeather, Zephyrs, and the Mindflayer allow you to sweep most boards in your favor. Especially against decks that like to take it slow at the start of the game. However, its the midgame that really makes this strategy work. Disciplinarian Gandling is the key to turning your low value minions into a swarm of failed students. While not as effective as in decks built around his effect, turning Bloodmage Thalnos into a 4/4 novice engineer is a pretty powerful play. Gandling turns a lot of your slower plays into tempo plays by popping the death-rattles of Reliquary, Thalnos, SN1P SN4P, and the Mindflayer. In addition, he also upgrades a lot of the crappy stats of your more effect orientated minions like Kazakus, Ilucia, Mankrik, and Zola. On the flipside, he also stops you from playing much of your bigger stuff, so he should be aggressively traded away once his effect has been made use of. To help close out games, Shadow Hunter Voljin, Overlord Runthak, and Flightmaster Dungar help remove threats and provide a final push to the end of the game. 

Disruption: This deck's tech options are tutored against combo decks who normally can survive your onslaught of legendries and OTK you. This strategy is by far the most difficult to pull of, but can devastate opponents who you read correctly. Your key companions against OTK decks are Murozond, Mindrender Illucia, the Nameless One. Most combo decks will aggressively draw into their deck to acquire their win condition and to counter that, you'll have to rely on the Nameless One. His silence ability can stop the drawing power of decks that rely on Northshire Cleric, Loot Hoarded, Thalnos, ect. However, your main disruption tools are Murozond and Illucia. the mindrender's ability to steal your opponent's hand allows you to surgically remove combo pieces, while Murozond can copy the effects of an opponent's combo turn (assuming you aren't already dead that is). The most important thing is to dump your hand of powerful cards before you commit to the disruption plan. Otherwise it may backfire on you.

So those are the win conditions and all their strengths. One of this decks only advantages over other decks is your ability to choose which strategy you want to play, so make sure you commit to one victory condition and full send it. Cards like Zephyrs, Kazakus, Flightmaster Dungar,  Zola, Malygos, and Murozond all depend on which win condition your going for. In any case, if you actually intend to play this deck, get ready to lose a lot in the beginning, its a really weird deck to play for an all legendary experience.