Then you use the spell Shrapmetal by rushing up to an opponent until you are in contact range, hit "Return" to enter turn-based mode, and cast the spell. The reason for doing it this way is to make sure that no shard of metal misses, and the same opponent get the benefit of all of them. At master level, this shoots out 7 shards, each one potentially doing [6 + (1d6 x skill)]. For a skill level of 26, this works out to an average of 209 points of potential damage per shard, so the total is in theory 7 times that. In practice it doesn't work out that high, because virtually all the monsters you'll be using it against have a degree of resistance to damage. However, three casts of Shrapmetal will always kill a gold dragon, which is the toughest of the routine monsters (1300 hit points) and I have occasionally killed one in two casts. This spell does physical damage, so it won't hurt anything immune to that, such as oozes and diamond gargoyles.

There's nothing in the Tomb of Varn which comes even near to withstanding that sort of treatment.

Dragon Breath is another Dark Magic spell. Again, for a dark magic user with 26 skill levels and equipped with Guinevere and a Ring of Dark Magic, it potentially does (1d25 x skill) [i.e. an average of 754] points of poison damage to everything in a 512-unit radius of the impact point. It won't hurt anything immune to poison, such as Guardians of Varn.