Path of Exile's Wintersbreath Brand is a powerful but complex skill. It attaches to an enemy and deals damage to it while a sphere of icy energy surrounds it. This sphere does not damage any monsters, but when the brand drops off the enemy it applies a debuff called Winter's End which deals damage for one second. To make this skill effective, it is important to make it drop off frequently. This can be done by overwriting the brand with a fresh one, killing the monster it is attached to, using brand recoil to pull it off, Exchange it by Poe Currency or using the mastery that makes it jump to a new enemy.

It is important to note that Wintersbreath Brand is actually a debuff which causes cold damage over time. This means it is not classified as a hit, so it doesn't work with effects such as Life on Hit or Vile Toxins support. It also cannot leech life or mana, as it is a dot. Additionally, it cannot crit and cannot be reflected back to you.

The saving grace of this skill is that while it is attached to an enemy it ticks based on the activation frequency of the skill. Each tick adds a stage and each stage causes the debuff to deal 20 more damage. You can increase the max stages by 4 with a lab enchant for a total of 480 more damage. You can also attach up to three brands to an enemy which stack, however you need the Rubenbinder keystone to do this.

In order to increase the damage of this skill, you can increase the activation frequency with cast speed or brand activation frequency and for duration, you can use skill effect duration or brand duration. It is important to note that the skill does not apply damage at the activation frequency, so once you have max stacks, you can add as much duration and cast speed as you'd like and it won't increase your total damage.

Overall, Wintersbreath Brand is a powerful but complex skill. It can be a great choice for early game, but its damage can be lacking in the end game. You can ramp up the damage with the correct investments, but it will require a lot of attention to ensure you are getting the most out of it.