Phantom Assassin

Mortred the Phantom Assassin is a melee agility Hero fitting the role of hard carry. Mortred is best-known, and infamous for, her ability to inflict staggering damage with single strikes. Her abilities synergise supremely well with each other, rendering her an extremely formidable foe once she has acquired the items she requires. She is a very farm-dependent melee Hero, but she farms creeps with much more ease than many of her fellow carries, using her Stifling Dagger for last hitting. Besides eliminating the weakness most melee Heroes have in their farming, it also saves her from expending gold on important melee carry items like Quelling Blade. Her second ability, Phantom Strike, acts as both her escape and initiate, while Blur gives her an edge against other Heroes that depend on their physical attacks by evading them; giving her partial damage immunity to many carries. Her ultimate, the strongest critical strike in the game, is what connects Mortred with four-digit damage and what gives her a place amongst the very best support killers in the late game, since they usually fall instantly from the divine strike her ultimate provides.

Tips

 * Stifling Dagger has multiple uses. It should generally be the first skill maxed, as it allows you to last hit creeps even if they are far from you and later on allows you to slow enemies at a great range.
 * If you are being harassed out of melee last hit range and are relying heavily on Stifling Dagger to last hit, consider purchasing a Ring of Basilius for mana regeneration. This should provide you with more than enough mana regeneration during the laning phase, and should you need it can later build into a Vladmir's Offering.
 * Avoid using Stifling Dagger as a harass tool in the laning phase before level 5, as you'll be losing a good amount of CS and it won't deal enough damage to ward off your enemy. However, you should use it on enemy heroes when they back up and attempt to use non-combat items such as Clarity and Healing Salve.
 * Depending on your team's strategy, Phantom Strike can be taken at level 1 as the increased DPS combined with allied disables can secure First Blood.
 * Phantom Strike can target allies and enemies. Jumping to a friendly unit can be useful if Mortred needs to escape.
 * Leveling Blur is usually not recommended early on. However, a single point can be very helpful if your lane opponents are primarily harassing you with basic attacks, or orb-walking.
 * There is a temptation among unseasoned players to focus on the maximisation of attack damage, neglecting attack speed. However, focusing on attack speed generally produces more favourable results; her critical damage is gigantic even with low attack damage and high attack speed means she is much more likely to kill her target, as opposed to relying on huge-but-infrequent criticals. In essence, the faster her attack speed; the less likely you will fail to kill a target because of lack of luck; and three Coups de Graces with average base attack are much stronger than a single one with high base attack.
 * It is not advised to build Mask of Madness on her for increased attack speed in a similar manner that it is built on heroes with bash, as Phantom Assassin has very poor health and has no means to disable her opponents from attacking her while she is more vulnerable under the mask's effects. Examples of heroes with abilities that pair well with Mask of Madness include Faceless Void fighting inside Chronosphere, and Spirit Breaker's Greater Bash, Charge of Darkness and Nether Strike disabling an enemy's ability to retaliate.
 * Be very wary of enemies using Blade Mail, as Mortred's damage output is many times greater than her health pool, though with a Black King Bar you can alleviate the issue if the enemy does build a Blade Mail.
 * In the laning Phase of the game sometimes if you are facing severe harassment and your team is incapable of giving you the space to farm your items you might want to consider building a Mekansm on your hero as her skills hardly use any mana and because of her low health pool Mortred can get up to 1/3 of her health back early on and contribute to her team earlier. This item gives you more survivability against both nukes and physical attacks. Though building a Mekansm is VERY situational on a hard carry.

Trivia

 * Mortred is derived from Mordred, a character in the Arthurian legend who betrayed and fought King Arthur at the Battle of Camalann.
 * "Coup de grâce" is a French term (that bled into English) which literally means "blow of mercy", and refers to the killing blow of a wounded person or animal, friendly or not, to end their suffering.