- POISONED BLADE: Starts with the APHEELSIK glyph, gains 40% bonus damage against poisoned monsters.
- LIGHT FOOT: Exploring the area around a monster gives the player first strike.
- SWIFT HAND: attacking a lower level monster always grants an instant kill. This will overwhelm every other status effect in the game.
Note that spaces that fall off the edge of the board count as "revealed" for the purpose of light foot, so you can gain first strike against edge-hugging monsters in this manner. The swift hands ability ignores abilities such as first strike and death protection, meaning you face no risks when attacking monsters like gorgons or animated armors as a higher-level assassin. In rare scenarios where the boss is lower than level 10, it's entirely possible to kill him with swift hands.
With an emphasis on attack damage, the human assassin Human Assassin makes for a more combat-oriented assassin. He is better at regen-fighting monsters and will be well-suited to poison antics. The downside of the human assassin is that the only class feature the Assassin has to synergize with high attack damage is his situational first strike. You'll need to find other combos to make up the difference.
One of the most powerful spellcasting combinations in the game is the elf assassin Elf Assassin. With vastly expanded mana, the elf assassin makes a potent spellcaster. The biggest difficulty that dedicated spellcasters face is that they often neglect their attack damage and have difficulty fighting lower-level monsters that should be easy. Using swift hands, this is not an issue for the assassin, allowing him to focus totally on spellcasting in a way that even the Wizard cannot. Other races can still make potent spellcaster assassins, but they won't be as good as the elf.
The goblin assassin Goblin Assassin is the ultimate class/race combo for level-up catapults. By using swift hands to kill weaker monsters and converting items and glyphs for extra experience, a goblin can gain as many as five levels over the course of a boss battle, fully regenerating his health and mana each time. Very few bosses outside of vicious difficulty can survive this sort of persistant onslaught, and since you can begin the boss battle very early with this character it's likely you'll be able to use poison antics as well. The Goblin Assassin is one of the best ways to obtain the Unstoppable, Ding Max, and Feeling Parched badges all in one go!
The Assassin is one of the game's most potent classes, and is well-suited to a wide variety of approaches. At low levels, he has a strong and reliable opener with the APHEELSIK glyph, and at high levels he can cleave through strong monsters to gain a few extra levels that can make the difference. His greatest weakness is that he has very few class features to improve his combat abilities, and capitalizing on his situational First strike is very important. Because he has no bonus to regeneration or resistances and his initial attack bonus against poisoned monsters is only 20% (net), the Assassin actually makes a sub-par regen-fighter without additional items or boons. The assassin is most similar to the Fighter in this respect, and he can build towards almost any type of character by using the right combination of bonuses.
Although at first glance it may not be apparent, the Assassin is actually a very strong class for spellcaster strategies. One of the biggest problems dedicated spellcasters face is that they neglect their attack damage, and may be easily worn down by low-level monsters. An assassin will never face this problem, even on vicious-difficulty levels, and can therefor focus all his attention on the boss.
Because the assassin can easily 1-hit-kill monsters that are lower-level than him, he should never fight a monster that is equal-level to him unless he has no other choice. There is no bonus XP given for defeating a monster of equal level to yourself, and once you gain a level you can kill him effortless. Always focus your efforts on fighting stronger monsters to earn bonus XP.
The Assassin works well with a broad range of deities due to his personal flexibility. Unless you're willing to eschew the poison glyph, you will probably want to avoid Taurog and the Glowing Guardian. Otherwise the Assassin will work flawlessly with any other deity.