Well this is as title says a Garen(DEMACIA) tank. He isnt usually a tank but if you make him a tank he can do really well for his team. As of Garen the best to get in beginning is judgement. His judgement is a good way to start off because it deals 50 every second. later in the game he should b tanky enough to take down at least half of health of other tanks cause of his runes.

P.S. This might not be that good but I'll do my best to make it work.
P.P.S. As well it might be as accurate as I would think.
P.P.P.S. THIS.I.REPEAT. THIS iS ONLY MY FIRST POST OF A BUILD!!!!

I might as well get this down.

Phantom Dancer in the end is to just make it easier to attack weaker health players like ranged.

Thornmail is a good way to for all tanks to be indestructable by melees.

As well you can always take out any items you want and add another warmog's for some more health. He will then have about 5k health which could prove useful in turret diving into the nexus for a kill.

The runes help him to go get a good start in the game. When he versus a melee like Yi he can easily block most his basic and magic attacks so he'd only take very little damage.

His masteries are what also makes him have a good start. the defence helps block some of magic and damage. He also gains some health.

Pros:
[*] Garen has an early game advantage
[*] He can be almost indestructable if you can play as him
[*] He can basically solo two melees if u know what to do

Cons:
[*] Garen's masteries and runes might not be as good as in early game
[*] Garen can save teammates with his tanky build but won't always save them 100%
[*] He can't go 1 v 5 as like any other champ(You can try. If it works you're defintely really good with Garen).
[*] Slows, stuns, and snares can definetly get u killed in a 3 v 5

It's best to use silence to stop the closest melee from using an ability in 1 vs 1(also works for a range). You can charge right in to grab all attention to you and get away(you may die like in cons). Best in hide in bushes to weaken them a lot and your teammate will come to help and you can turret dive and get the kills.