If you ask about who’s the best support in DOTA 2, maybe Crystal Maiden will be on your list. Why ? Because she have capability of becoming a full support. She have disable skill, AOE skill, Buff skill and her ultimate skill is devastating.
Rylai is a ranged hero with INT primary attribute. Her speciality is ice, she can control ice, that’s why all of her skill was made by ice. As a support, she also good at ganking with disable skill and debuff skill.
For harassing enemy, Crystal Maiden will use his first skill, Crystal Nova. With this skill, enemy inside the skill AOE will take magic damage and taking slow effect ( 50% movement speed slow ). This skill also give you 900 ground vision, so it’s good for opening map, specially FOG area.
Her frostbite skill can disable any enemy heroes movement for 3 second. If you using this skill to creeps or jungle monster, the duration will increase to 4.5 second. FYI, when frosbitted, enemy still can use item or skill as long is not a channeling skill.
As a support, she have Arcane Aura. It’s giving a mana regeneration to teammates hero. This skill is very usefull, specially for spamming skill hero.
The most devastating skill for Crystal Maiden is Freezing Field. Maiden will open a large area and calling the snow blast. Enemy hero who stand inside the area will take magic damage and slow effect. If you buy Aghanim Scepter, it will trigger Frostbite skill too.