Each Phantasm has its own role to play but they all tend to come down to one thing: dealing damage and lots of it. Like Illusions, Phantasms are temporary summons that only last as long as your target is alive or until they are killed. Phantasms can be easily identified by the fact they are a transparent and pink in colour and tend to have a unique appearance based on their role. For example, the Illusionary Duellist wields twin pistols. Just like Illusions however, Phantasms have very little health and can be killed incredibly quickly. Ensuring you use them at the right moment is key to maximising their damage.
If you had asked me several months ago whether or not I thought that the Sword Offhand was worth using, I would have said no. Compared to the pistol, it doesn’t seem a particularly viable choice. However, I have come to love and favour a Sword/Sword play style over Sword/Pistol. The Phantasmal Swordsman is great for several reasons, the first being that it actually acts as a Leap Combo, meaning when you use the skill you too gain such Combo benefits if in the right Field. The Swordsman also deals considerable damage (in excess of 5,500 with the right builds) while also being capable of avoiding damage because it leaps in and out of combat. The fact you can also have its cool down to as little as 9 seconds makes it formidable.
I still consider the Mage the worst of all the Phantasms. As good as retaliation can be, it lasts for very little time with the Mage and the confusion stacks are very low although its duration is 9 seconds. As the only Phantasm that truly benefits from condition damage (the Warlock works amazingly well with 0 condition damage) it compliments excellently with the use of Scepter. I will add that as retaliation stands, it can be a very powerful boon and works wonders with the trait, Confusing Cry. I’m still hoping that the Mage receives a bit of a buff as there’s a reason you never see any torch mesmers; it just isn’t very good.