So here, I am going to go over why this even works in the first place. So first of all, Jarvan's E ability () does a nice chunk of AP and Aery can boost this a bit. But the real synergy comes with the attack speed buff that is given to nearby allies. When you use your E you will continuously shield your ADC due to the buff lasting for a bit. After is built, your E will not only shield and give your ADC attack speed, but also heal them as well. See the video below:

This is definitely one of Jarvan's more powerful phases. Use your E to deny enemies who are trying to poke and farm. You can also use it proactively to shield your ADC from attacks. Watch for and early rift fight as your knockup, damage, and shielding can sway an early 2v2. During the first few waves you should be proactively playing around the enemies, with ADCs like Draven and Tristana go for constant early/LvL 2 engages and for other ADCs like Vayne or Senna you want to always be shielding them from damage to allow them to farm up during the lane.

Jarvan is very powerful during the middle of the game. He can follow his Mid, Jungle, and ADC around and constantly engage, guarantee kills, and heal/shield. Following a fed Jungler could win your entire game. Try to find who is fed and pocket them around the map, if your ADC just needs to farm try and allow them to sidelane while you follow your, for example, fed Talon around the map and help them constantly secure kills. Or if your Draven is coming out of lane 3/0 then follow him around and keep setting up kills and speeding him across the map. ALWAYS be watching for fights and skirmishes in the jungle and around objectives. You are so helpful in these fights and can secure early drakes and Rift Heralds.

This is by far Jarvan's weakest stage of the game. You can Speed, Shield, and Heal your allies during teamfights. Mainly look for big ults and quickly leave the ult while sending flags in to boost your teamates. If you decide to finish a Redemption you can have huge heals and speed ups. Pair your ult with other ults like Miss Fortune, Illaoi, Aphelios, etc. Watch for Assassins and be ready to stopwatch.

Thank you for reading through my Jarvan support guide! Leave a like and comment if you enjoyed it.