Swain has been my main combatant in League of Legends for almost a year now, being able to fit in many team comps whilst simultaneously being one of the few AP champions that can counter the new "Rengar and/or Kha'Zix straight AD unfair assassin" meta that seems to be lining the Rift as of late. With his kit he is able to subdue melee threats with ease, and dive head-first into a team to initiate.
However, his glaring weakness against long-range, high burst champions is becoming all the more apparent with the current mid-lane meta - and I've personally been having incredible success with him in top lane due to his kiting ability! Adept at shutting down champions such as Tryndamere and Riven, he's able to complete remove an enemy champion from play and keep himself growing!
Over the course of a game Swain's strength evolves, changing him from an early AP Carry to a late-game off-tank. Many assume that Torment is an ability designed so he can deal extraordinary damage, but in my view it is in-fact the exact opposite: It allows him to build less AP and more defensively, whilst still dealing damage! Through this build, this monster of a top-laner will become one of the tankiest casters in the League!

- Make sure to neck down some Elixirs at the late-game! Swain can reach up to 404 AP with an Elixir of Brilliance at level 18, which is rather extraordinary when you consider his armour, sustain and MR!
- Zhonya's is one of Swain's most useful items, because his ultimate will continue channeling even when you use the Stasis passive! Consider finishing it before Rod of Ages if you fear tower dives, as it'll allow you to keep the enemy pinned whilst healing!
- While it is advised to land your E before the rest of your skills, don't feel as if you have no other approach.
- The damage boost on Torment also applies to auto-attacks, which comes in handy during early-game harass. Consider Hybrid pen runes in order to dish out maximum lane-harass for cheap costs.
- While Swain is a monster at close range, one of his greatest weaknesses is his lack of range. Consider Alacrity boots, Ghost and Flash in order to close the gap against champions such as Syndra, Annie and Caitlyn.
- Ravenous Flock uses more and more mana the longer it is on, so be careful when using it - ESPECIALLY early game. Whilst sustaining in lane, I'd recommend 3 second uses of the skill or approximately 3 raven bounces. This'll allow you to keep mana expenditure low.
- With experience and time one will become adapted to Swain's passive and not need mana regen early game. However, if you're having trouble don't hesitate to get a Chalice early.
- Nevermove is a SNARE, and not a stun! Beware of ranged champions that can keep fighting on even whilst immobile!
- Rylai's is a highly viable 6th item, and in general a potent item on Swain. However, the lack of MR or mana regen it grants makes it a dubious purchase. Consider the enemy team comp, as well as your control of the blue buffs before purchase.
- Grievous Wounds from Executioner's Calling, Ignite, Fizz, Tristana, Morellonomicon and Miss Fortune (Among others) severely hampers your healing potential. However, Zhonya's Hourglass can counter this for a few seconds. Spirit Visage also lowers the healing reduction, but it will remain a burden regardless. Consider taking Cleanse as a summoner spell, or even replacing Athene's Unholy Grail with Mikael's Crucible! (Off-Tank Support Mid?!)
- Swain is absolutely vicious with the red buff, and is one of the few mages in the game that can make extensive use of it due to both his Q and E reproccing it with every tick! Combined with Liandry's, the sheer speed that targets melt is extraordinary!
- One of the key points that separates a good Swain from a fantastic Swain is his ability to land his Nevermove - it being an incredibly strong initiation and peeling move. Remember to lay it in your tracks when retreating, or zone enemies out by placing it at choke points!
- Make sure to try and focus your spells on a singular target during team-fights, as while Swain has strong AOE damage his ability to melt foes is limited to whoever he has his E and Q channeling on!
- Base your build over the role you need to fulfill! Swain can still be highly efficient built in a more traditional mage sense!