You want to scale and he is a very good at scaling right now
The only way you can level morde up. There is no reason to do anything else. Q for cooldown and damage, E for cooldown and %magic pen, W for cooldown.
Very good sustain and damage my preferred runes for this season
From my testing this is the best ap build.
Matchup breakdown
Pros
- Good sustain
- Resourceless
- Not mechanically challenging
- Good waveclear
Cons
- Immobile
- Weak early
- E is easy to dodge
Early Game
Morde has a relatively strong 1-3 so against tanks try to get a lead and make their csing very hard. Against champs like renekton or darius be a little bit more careful as they can win the trades so aim to at least go even. Dont be afraid to use abilities to farm but keep in mind they can punish you for it while they are on cooldown. try to use the first cast of W at the start of a trade and use the second cast only when its over so you maximise the shield. Morde is very strong lategame so if you just have good farm and stay 0-0 it is still fine.
Mid Game
Morde has good split potential and teamfight potential. If you want to split just keep in mind that your team should be pushing or doing something useful in the map as well so your pressure isnt wasted. Having your ult usually means you can stall the enemy if they go for you for up to 10 seconds and isolate one that you can kill in the ult. Even if you dont get a kill as long as your team did something its all right. During fights depending on where it is you want to either get the enemy jungler so they cant smite an objective or just ult the strongest enemy champion. Even if this doesnt lead to a kill you can at least deny them of their strongest player for 7 seconds.
Late Game
Keep in mind that by this time the enemy might have quick silver sash/spellshield so you cant ult the people that do. Splitting is still an option but by this point either you have taken all t2 towers or you are at a disadvantage where you cant properly do so anymore. You can make picks with your E if possible and try to not imediately ult someone if you have a numbers advantage. Now you have 2 choices in the R usage.
1.Either you ult the tankiest enemy so you get their stats and just remove a nuisance from the teamfight because tanks usually have a lot of cc.
2.You ult an assasin or whoever is getting to your backline consistently and rendering them useless for the fight.
3.Ult their biggest damage dealer.
Whatever your decision make sure you are vocal with your team so they know how to play around it. (Assuming they have the capacity or care enough to utilise it)