Text on unlock
"Well done! As a reward for completing your first run through the Snake Pit, you've unlocked the TRANSMUTER class! Veteran players have to contend with a lack of natural health and regeneration, but are given the power to blast dungeons apart and get healed by the very walls themselves."
As a Transmuter, you cannot gain health by exploring, only by using ENDISWAL. However, due to the low mana cost (1 point) for ENDISWAL, it is easy to regain health cheaply. The basic strategy for taking down higher level monsters is to uncover a portion of the map with many walls, then to attack the higher level monster. Once you are about to die, go around using ENDISWAL on the walls revealed prior to attacking the monster. It is important not to reveal any new hidden spaces during this time as this will cause the monster you've attacked to regenerate health. Keep on attacking the monster and using ENDISWAL on existing tiles until the monster is dead. If needed, you can try to minimize the exploration of new tiles if you run out of mana for healing. In the end, it becomes a balancing act between revealing tiles and healing yourself, as the only regenerative effect you have is with mana for revealing tiles.
BLUDTUPOWA still boosts the Transmuter's mana regeneration, so you can take it, activate once and have a pleasure of quick mana regen.
Note that it's important to heal as much as possible before exploring. That is, if you're hurt and your mana is at 100%, you should definitely be healing yourself. Otherwise you are not regenerating any new mana by exploring and at the same time not healing yourself due to the class trait.
Getting poisoned is fine since you cannot regenerate health automatically by exploring.
If you come across the Stone Heart in a shop, buy it—its bonus stacks with the Transmuter's existing Stone Armour ability, doubling health regeneration.
Race and Deity Choices
Choosing Elf or Gnome for race is a good choice as it gives you both flexibility to cast spells other than ENDISWAL and at the same time have enough mana to take down higher level monsters. Gnome is preferable, because having more potions is better than having a higher mana limit.
It should go without saying that the best deity to choose is Binlor, as the Transmuter's heavy use of ENDISWAL generates large amounts of piety. Note that Heroics, a boon which takes you to 10 level instantly will mean, that you heal 20 HP by blasting a single wall. Thus, with 15 mana points you will regenerate 300 HP. Choosing Taurog is absolute suicide since it dislikes Glyph usage. Dracul can be helpful for a secondary source of health regeneration and extra tanking capabilities. Jehora Jeheyu should also be noted, due to giving piety for wall destruction as well. Aside from those, nearly any god is a decent choice. Since Alpha:The Earthmother dislikes ENDISWAL it might seem a bad choice at first. However since her punishment is ineffective against Transmuter (who already have zero natural regeneration) it's just a matter of having 10 blood pools and two enemies to stone to earn stoneform, and then ignore her restrictions.
The Transmuter should find it relatively easy to beat the factory through perseverence and correct use of ENDISWAL. Race choice remains the same as above, though it may be more beneficial to go with Jehora Jeheyu or Dracul than Binlor. Seek high-level Golems to destroy, as these are the easiest enemies to take out without using up too many walls. At first you should be able to take out Golems 1-2 levels higher than you, but once you reach level 5 you can take on level 8 or even 9 golems with ease. Leave as many low-level golems and meat men around for midfight leveling later, and only use (mana!) potions for taking out monsters far above your level.
Finally, when you reach level 7 you can go for Iron Man. Make sure you have plenty of walls exposed because you don't want to have to explore during combat. If your maximum mana is not high enough by this time, you will probably not have enough walls left to take out the Super Meat Man, so do your best to increase max mana early. Once Iron Man is dead, if you still have about 3 of both potions you can safely explore the entire map, exposing all of the walls and hoping to increase mana capacity if possible. This should enable you to take out the Super Meat Man. If you don't have enough potions, try midfight leveling with the Golems and Meat Men you've left behind.
Generally speaking, Wraiths will pose a threat here due to their mana burn and should only be taken on if close to gaining a level, focus instead on higher level Vampires and Zombies. You'll need to remember to heal with ENDISWAL as you encounter Vampires (due to life steal) as the Transmuter has no other way to do so.
A very solid strategy (that requires BURNDAYRAZ and to a lesser extent BLUDTUPOWA) is to locate Binlor as soon as possible, around level 3-4 pick up Hardiness (+25% physical resist) and continue leveling until you've gained 100 piety for Heroics. At level 10 with enough walls uncovered you can easily approach Frank the Zombie. The Tormented One will present a challenge if taken on with melee with its 60% physical resist, BURNDAYRAZ will be essential to finish the dungeon. With enough potions (2-3) you should be able to defeat it (Binlor's retribution for other glyph usage should not matter at this point).
The Snake Pit should not be a challenge for the Transmuter; Serpent poison is ineffective and healing over 50% between hits on Gorgons should be easy. As always you'll want to avoid Nagas until you're high enough to one hit them.
Once you're high enough to level to 8 or 8 already begin attacking Jormungandr, having enough walls around to heal throughout the battle. Binlor's Hardiness will come in handy as always but will soften his blows, possibly allowing you to get through the battle without using a potion (depending on race).
Medusa should be of little challenge too, with a high enough mana pool and attack power she should pose little threat.