Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Threats to Sona with this build
What You Need To Do As This Support.
Remember Your Job Is Not To Do The Most Damage As This Support. But it is to peel and tank for your adc. This build helps give your entire team speed buff and shield/healing buff. You can also tank for the adc being semi tanky with the items you get. You will also have a lot of cooldowns so be sure to use the mana wisely or your team will be dumb and die.