Zero Duration Titan with Ember Fusillade + Time of Need. You don't need a guide: buy any affordable Dusk Vigil with the max level of fusillade available for your current level. In the passive tree just rush all the reduced duration nodes. Grab the increased duration nodes on your weapon swap and use it for curse or Thunderstorm or Flame Wall. Get your second ascendancy as soon as possible grabbing Hulking Form. With the rest of the tree you can experiment whatever works best for you (crit, non-crit, exposure, penetration, infusions, % damage, cast on ailment with high flammability...).
Once you reach the endgame you can use a level 19 fusillade Dusk Vigil or swap to wand + focus. If you save enough you can buy a Palm of the Dreamer with enough reduced duration to make your fusillade's hover delay shorter than your cast time without the need of support gems. At that stage Time of Need with compressed duration will make you immune to 99% of the degens in the game. You can google zero duration titan and you'll definitely find a guide.
Be quick because it's not going to survive the nerf hammer when 0.5 drops.