So I'm new to Mobafire so please don't hate. Malphite is honestly one of my best champions and the thing I love about him is that even though he's a tank, I get tons of kills as him. Now you might be thinking, wait he's a tank, he's not supposed to get kills. He's supposed to initiate and disable without dealing that much damage. However, the great thing about Malphite is that his E, Ground Slam, gains magic damage equal to 50% of his armor and with his core build - Sunfire Cape, Randuin's, and Frozen Heart you've already got incredible armor. However, his W, Brutal Strikes, increases his armor and attack damage by 40% giving him over 400 armor and thus a total of 200 bonus damage on Ground Slam.

So the key to playing Malphite is building health and armor. Ultimately that's all you need with him because his passive scales off max health and he gains damage from building armor. Once you've got your Sunfire cape you can clear minion waves pretty quickly with a Ground Slam and the passive splash damage from Brutal Strikes. The build is mostly centered around maximizing armor but also serves as an incredible anti-DPS. The combination of Randuin's active, Frozen Heart's passive, and Ground Slam reduces enemy attack speed by 105%. Most DPS champions are comparatively squishy except for their incredible amounts of lifesteal. However, with armor over 400, they will deal next to no damage to you and will take sustained damage in a fight against you.

One thing I noticed when playing Malphite was that I liked to poke with my Seismic Shard which almost always resulted in me being mana-starved. Which is why Frozen Heart is an incredible item. It stops you from being mana-starved, gives 20% cooldown reduction which allows you to Ground Slam and ulti more often (I almost never have my ult down when I need it), gives 99 armor (so pretty much a Thornmail) and passively reduces enemy attack speed.

So the core build is Sunfire Cape, Randuin's, Frozen Heart, and Force of Nature just because the other team is bound to have some magic damage. For boots, you can either go with Merc Treads or Ninja Tabi depending on the enemy team composition and how much CC they have. For a final item Warmog's is nice if you really want to be utterly tanky but a Thornmail can increase your anti-DPS role to the point of absurdity if you want to face-roll a team with poor composition. If the other team is mostly magic damage, then Banshee's Veil is the top pick as you get extra health, magic resist, and mana to keep you from running out in a fight.

For summoner spells I take exhaust and ignite because I want to get kills and face-roll people. If someone manages to escape from a fight they will inevitably lose with you, ignite takes care of that. Also, exhaust increases the amount movement slow you're already going to be doing to them as well as prevents a caster from whittling you down by reducing the damage their abilities deal. Plus if a DPS champ or a caster with incredible amounts of spell-vamp (Like Akali or Vladimir) happens to be life-stealing/spell-vamping their way out of being destroyed by you, the 50% healing reduction from ignite usually takes care of it.

So sorry this guide isn't terribly organized but I hope to come out with more in the future and maybe have them be more polished. They'll mostly be along the lines of tanks that are a threat.