Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
The objective of this build is to utilize the awesome power of Righteous Gust for the purpose of establishing an early lead in the lane phase. Once achieved, your ability to support team fights and turret defense will solely depend on your ability as a summoner.
This is not a fancy or unique Galio build by any means, however; I believe if you are the type of player who regularly uses Galio offensively with highly coordinated, attentive players, look no further. I recommend this build for use with teams without focus on AP champions. This will reduce the likelihood of the enemy team stacking excessive magic resist. If successful, Abyssal Scepter and Void Staff will allow for some hard-hitting Righteous Gusts and when the chance presents itself, a punishing Idol of Durand. Good luck!
Mecury's Treads (1200g) - I start the game with boots and rush Mercury's Treads as quickly as possible.
Spirit Visage (1250g) - This is always my second item. It is great for self-healing if you effectively use Bulwark on yourself and teammates.
Chalice of Harmony (890g) - Every good Galio will need this item at some point. I prefer to get it immediately after Spirit Visage but I do eventually sell it once I reach level 15+ to make room for another item, depending on the circumstances.
Abyssal Scepter (2650g) - This is normally my 3rd or 4th item in a game. Your fellow AP users will thank you for getting this item. More importantly, this will tilt the odds back in your favor if the enemies wear magic resistance items.
Void Staff (2295g) - I always get this item after Abyssal Scepter to let the other team I am not bullsh*tting with them anymore and they need to die more often. With the lowered magic resists from Abyssal Scepter and your newly acquired Magic Penetration, your abilities should leave a nasty bite.
*Force of Nature (2190g) - If the enemy team is primarily Magic Damage and/or you just want to do a bit more damage, try this item on for size. The health regeneration ties in nicely with regular Bulwark usage. You will almost always be ready for a team fight when wearing this.
*Thornmail (2000g) - I purchase this item when the enemy team has 1-3 high Physical Damage champions (Twitch, Olaf, etc). Imagine their surprise when Thornmail boosts the damage output for Idol of Durand significantly because Thornmail returns 30% of damage taken as magic damage.
*Zhonya's Ring (3460g) - If you are interested in increasing your Ability Power by 25% and utilizing a shield that blocks incoming damage for 2 seconds, this item is for you. If I am being fed consistently, I normally get this item after Void Staff.
Begin with Boots, Health Potion (x2), and Mana Potion (x1). Max Righteous Gust as early as possible. It does good damage early game and depending on your lane partner, can set them up for easy minion kills. Play defensively until you reach level 6 and obtain Idol of Durand. Once you (and your lane partner) have sufficient health and mana, look for your first target/s. Gank according to the skills & abilities of your lane partners and opponents. DO NOT hesitate to assist another lane via teleport + Idol of Durand as long as your original lane doesn't suffer from your absence.
If you are lucky enough to snag the 2v1 lane because you have a Jungle Champion on your team (Amumu, Fiddlesticks, Warwick, etc.), the same rules apply. However, pay strict attention to your mana consumption and only use Righteous Gust to harass, especially when both minions and champions are in the path of your ability. You may need to teleport between levels 4 to 6 to refill your bars. Once you return, use your abilities aggressively until you are out of mana. With your mana bar empty, charge at an unsuspecting enemy. They may be confused or even happy to see a manaless Galio rushing towards them. Clarity must be refreshed and ready to use prior to engaging the enenmy. Once you are within sufficient range, use Clarity, maybe a Righteous Gust to close any potential gap, then Idol of Durand. Hopefully, you should be able to land a kill or two. I use this strategy often in the 2v1 lane and it almost always pays off.
When your team is pushing, it is important to target the soft targets with Righteous Gust. Also, a good Galio relies on timing. Don't just think you can run in and press R. Observe which enemies have stuns, silences, disables, etc. More importantly, make a note of who they focus to ensure when time comes to use Idol of Durand, Alistair or Blitzcrank don't interrupt. Lastly, be generous with Bulwark and place wards strategically throughout the map. This will promote map awareness and greater access/control of the map with your teleport.