Ninja

The Ninja has all percentage based abilities which make it hard for survival until you get his percentages to a decent level.

Focusing on key abilities and knowing how they synergize can help but the bottom line is that the Ninja is not a main character to start farming Gold with. However, the Ninja (once leveled properly) can be the fastest farmer for later game, although more luck in finding Swords (DMG) and Health is needed than the Cleric.

Ability Focus
The key abilities to focus on early are Double Strike and Dodge. This allows the Ninja to strike Monsters twice without a counter-strike. Once a few Swords (DMG) are found, Double Strike allows quick dispatch of Monsters although the other two abilities (Instinctive Strike and Dim Mak) will allow for overall speed in the later game.

Ability Synergy
Double Strike works with Instinctive Strike to pre-strike Monsters without a combat round, softening them up or destroying them outright. Once Double Strike (and Dodge) is at a decent percentage, Instinctive Strike can be increased to make exploration quick and easy.

Dodge is a two-edge ability. It allows invulnerability but goes somewhat against Dim Mak. Dodge is the only ability that is not advisable to increase indefinitely. You want its percentage high but still allow the occasional hit to come through to trigger Dim Mak in early exploration for speed (before finding enough Swords and Health to make Double Strike and Dodge work). The percentage of Dodge seems to be good around 75% (level 490+). This allows Dim Mak to kick in with early exploration (for more speed) and provides enough protection to be effective after enough health is found.

The wording on Dim Mak is a bit misleading. Once Dim Mak is triggered (according to the wording) it applies indefinitely until healed above the percentage indicated (healing but remaining below the percentage does not remove Dim Mak). Dim Mak should be as high a level as possible because along with the Ninjas base level (see below) it allows survival in early exploration of a dungeon. After enough swords (DMG) and health are found, Double Strike (along with Instinctive Strike) and Dodge take over and Dim Mak no longer applies.

The base level of the Ninja synergizes with Dim Mak and Double Strike by raising health to a level that can take a couple hits (triggering Dim Mak) and raising DMG allowing Double Strike to double the DMG output (although finding swords will be the major source of DMG).

Speed Farming
Once percentage levels become decent, speed farming (quick games) is highly likely. Entering a dungeon allows Dim Mak to shine destroying enemies quickly (see Ability Synergy above) and Instinctive Strike to destroy Monsters (after finding enough swords) in normal exploration. While there is some luck involved, the percentages work in your favor and reaching the treasure quickly becomes the norm.

Exploration Stratey
Swords (DMG) is the Ninjas best friend. All unexplored tiles should be explored before any combat rounds begin and Swords should be gathered as soon as they are uncovered. This allows Instinctive Strike to be more effective when uncovering a Monster. Once every tile is exposed and only Monsters stand in your way, Double Strike is more effective (if swords were found) and Monsters that cover the most unexplored tiles should be taken out first (to find more swords).

The exception to exploring every tile before combat is when a Boss is uncovered. Multiple Bosses boost each others DMG and it is best to take down a Boss when it is first uncovered to prevent multiple Bosses appearing on the dungeon level at once.

Gathering Health should be done last unless the Ninjas HP's are too low to take a hit from any single Monster. This increases the chances of the Ninja entering Dim Mak. Gathering a low level Health (single bottle icon) can be beneficial if the Healing level wont kick the Ninja out of Dim Mak. The exception is if Health and DMG are at a very high level already and gathering Health will not make a difference.

Uncovering tiles quickly can also lead to finding the Door/Treasure and getting the Key relatively soon. The Ninja can bypass the rest of the level for speed depending on the circumstances.

The following circumstances can lead to bypassing a level:
 * 1) If Dim Mak is active (low health) and not enough swords (DMG) were found
 * 2) If Dim Mak is not active and not enough health was found (mid health)
 * 3) If Dim Mak is not active and not enough health and swords were found (slower exploration)
 * 4) If the number of Monsters to kill would give very little exploration

Of course, everything is a judgement call but getting to the Treasure quickly will be the major source of income.