So, to be able to play a valuable role in team battles,
the key setup becomes quite important.
First, the tank/warrior at the very front needs someone to take the role.
Next, the team also needs a mage to deal magic damage.
After all, if you have a "knife" team and the opponents all go for armor, or vice versa, all magic teams max out magic resistance, it makes the battle extremely difficult.
Lastly, there must be a character who can carry the team's weight — the ADC.
Because of the shooter's mechanics, it is the most unique in all of League of Legends.
It's the only one that can wear down opponents from a safe distance without limit.
Thus, by the time team battles commence, if the enemy has an ADC and your team doesn't, it's easy to get harassed and dragged around by them.
But there's a new problem that arises with ADCs.
Designers, in an attempt to balance shooters in the rift,
tend not to give them much sustainability.