Let's focus on roleplay. Remember all the pain and torments you've feel in your whole life. So now you're angry, you have to turn all your rage, your madness and your wrath against your enemy. DUNK!

First of all, when you come on your lane, you have to show them all who you are. Do not focus farm in a first place, take position behind your opponent and fight, as a man. So stack your passive and kill or die trying, by the way all can see your face whith "First blood" (as the killer or the killed one, doesn't matter).

The most important thing in League is not to have fun, but not to allow your opponent to have fun. With your itemisation, it's easy to reach this goal. So consider all minions taken by your opponent as an outrage for your mother.
You can customize the stuff as for example buy a scimitar (QSS) instead of a BT against a ap top with CCs, or take a phage first an complete triforce later against a range top with mobility.

Do not listen to mates who say "GROUP OMG" they are just ******ed. By pushing your lane you force 2 enemies to stay against you, so do not leave toplane except to steal buffs in the jungle (ally or enemy, doesn't matter). If you really want to help you team (xD moron) ast them to peel for you as an adc cause you're not sooo tanky :p .

To be a better angry full AD darius and to facilitate roleplay, METAL is required. Marilyn Manson, Iron maiden, Disturbed, Amon Amarth, Nirvana, AC DC, Nightwish, Dagoba... or anything else which goes well with the gameplay, shall help you to conduct wrath on your enemies and smash (DUNK) them all.