alright with malz you mainly wanna solo mid if possible or u might be focus 2v1 early game. be sure to stack your voidling in your spawn with your q spell. dont use a single spell at lv 1 just stay back and last hit minions. once you get your lv 2 you can try to e the other dude and chase it! your voidling will help u he'll go half life down easely and if he dosent care of your voidling (or he dosent pay attention) and he attack you then dont back continue atking him and flash/e to finish it. remember that you have potions, if he bought doran, he might have the adventage on you because of the 100 life. so be carefull if he dont back.you can use your potion during this harass if he dosent back. with malzahar, until lvl 6 u should be harassing too much. start farming without your e because it will force you to normal attack your minion to make your skill bounce. if your enemie try to harass you, q it and back until he get back. if u are missing mana, try to lower all minion's life so they will be half before casting your e. or it wont bounce and your mana will not regen enough. at lvl 6/7, you have your ult so the enemie champ won't cause too much trouble.farm with your e and push the lane and attack the turet. at this time you should pay a massive attention on your map, who is mia and ask ur teamates where is the champ if you dont see it in the mini map. the enemie will try to attack you wile you hit the turret. use your e and back if he still follow you, wile you are not in the turet's range (dont whait till he leave his turet range cause he will back) use w/r on him and if hes not dead finish it with q. if hes stil not dead he will back so you can freely attack the turet (be carefull on ganks cause its the best moment for them to kill you)

-first up is my mark, i use magic penetration. it is the best choise you can have.
-then for my seals, i use flat mana regen. you probably can swith for flat life,life per lvls, flat ap or ap per lvls.
-my glyph, i use cooldown reduction per lvls. you also can use flat cooldown reduction, flat ap or ap per lvls.
-My quintessence, i use flat ap. you also can use ap per lvls, magic penetration or movement speed.

with my build i have some magic pen, wich will be usefull the hole game.mana regen for early game(because you are not supose to spam your e on minion until lv 6/7).i like having cooldown reduction per lvl because early game you dont need that much of cooldown reduction. you will need it later in the game. with the blue buff it will raise it to 30%/35% wich is enough. flat ap are usefull the hole game but even more for your lvl 2 harass (with your e and voidling)

be sure you get your catalis as fast as possible its your onlee heal or you'll always back early game. if the game goes well get your roa before ur sorcerer shoes like the build sais. if not get ur sorcerer before. then im gueting zhonia as fast as possible because it's realy usefull with malz. if ur ult is on cd, normaly the enemie wont stay in ur w (exept if someone els stunt it) but with zhonia i did some 3v1(melee). wile im being chased i go in a bush, i cast my e on the lowest health enemie, i cast my q on all of them and w under me,then zhonia. exept if its top or bot big bush, the onlee way they can keep an eye on me (wile im zhoning) is by staying in the bush where i am, but my w (that hits a lot) will hit them and bring thier life low. or they will have to leave the w zone (so leave the bush) until my w zone is gone, wich my zhonia will be too. so i can freely dodge them. sometimes im using vamp steal with malz it's up to you.

to kill an enemie champ you want to get close by ganking or using flash. first you wanna use your exaust and q, then e(with rylais, your e will slow him too).then u wanna get even closer to you to have enough range to cast w/r without moving. if he try to run (without flash or skill because of the q you did before your combo and not at the end) u just need to come close to him before using w/r. if he attacks you remember that exaust reyoduce the enemie'd dmg so he won't cause so much trouble (exept if he stunt and then flash out but your exaust made him use his flash so it's quite a success. come gank later, he will have no issue

i use exaust and flash exaust to lower the enemie resist and to slow him so i can correcly use my combo. flash is realy usefull for a suprising charge becasue the enemie know your combo will kill him so he will sty away from your r range.

you can also use ghost/cleanse to run easely(in my opinion it dosent matter u will die anyway if you over extend)

you can also swich exaust for ignite. it gives another charge to your voidling and it gives bonus dmg

teleport is cool too if you tele/flash on a cute teemo backdooring top(:P)you get a garantied free kill.

in team fights you first want to cast your w in the midle of all. it will give adventage if they all stay in it. focus your q on certains champ like kat ult, malz ult, fidle drain(ult if you can see him before he tele)and other specific skill. if there's no champ like these, cast it with your w in the midle of all. if you see a low life champ use your e on it so it can bounce and mabe get the kill. use your ult(onlee if you are not being focus) if someone try to run away or a carry that is not in the midle of the teamfight. be sure to stay realy far you have a great range on w and q and you will be focus if you get too close. if the tank(s) or carry(ies)charge right in ur direction and dosent pay atention on the others, q them and try to back(without flash).if they still atking you and you are quite low life, use your w and zhonia (then flash out if they are still next to you).