I made this guide since there is no guide about malphite in Season 3. This guide is not the best but it is something. I won my games with it and I am actualy asking you to give some feedback to improve my Malphite build.
As MARKs I choose for magic penetration. You will not do that much damage but without magic penetration you wont do damage at all.
As SEALs I choose flat armor. This will help you to get threw the jungle.
As GLYPHs I choose magic resist per level. After 9 levels you will have better then flat magic resist. Your first attempt to gank is mostly on level 3 or 4, so you will get a bit more damage. But after that you will only have advantage of this choise.
As QUINTs I choose movement speed. As jungler you need to clear your jungle fast and be able to gank fast too. With Malphite's Q skill it helps a lot to get even more movement speed to hit your Q.
All these new masteries kinda freak me out. I am not sure if I took the right masteries and I would love to get some help to improve this.
As you can see I start with armor and 5 potions in the begin.
After a good jungle you go back when you got 1050 gold to get boots and your gold item.
All the other items are up to you when to buy, depends on the team you are against ofcourse. But most of the time I try to build as seen above.
As you can see you have 1 item left. This could be whatever you think is needed. Most of my games dont get this far so i rarely use it. A posible item would be an abbysal scepter.
A lot of jungle guides tell you to max E first. As jungler it is your task to give your carry more kills. Thats why I chose to upgrade Q first. This give you a better gank and more kills for your team.
The jungle is made harder but still pretty easy for a Malphite. Ask your team to help you with wolves and still let the mid player pull blue. It gives you more time to make damage or to get blue into the bush so you prevent counter jungling. If you get a bit help from your team with blue then the rest of the jungle should be easy. You still got 4 or 5 potions after blue so you could gank when you done red.