I'm starting a campaign and I think it'd be cool if I could be a human and have tremorsense. I know it'd be hard, but I'd be willing to take a lot of negative stats to counteract that. If it'd be hard to start with it, how could I get trained in it?
Noting that Tremorsense is an Extrodinary ability, at least in the 3.5 SRD, and starting with the following two discussions, Tremorsense??? and Ways to Get Tremorsense?, we find the following possibilities:
Take a template:
Take an alternate class:
Use a magic item:
Although not as powerful, you could instead:
Use the spell:
You can automatically pinpoint the location of any object or creature within 30 feet that is in contact with the ground.
Take a feat:
touching the ground, you can take a move action to sense the number of creatures within 20 feet that are also touching the ground and the direction to each one. You cannot pinpoint the location of any creature with this feat.
automatically pinpoint the location of anything that is moving and in contact with the ground so long as it is within 10 feet. The range expands to 20 feet if you are in an area covered in a layer of at least 1 inch of ash, dust, loose earth, or sand. This ability only tells you what square the creature is in, so you still have the normal miss chance from concealment if you cannot see the creature.
Benefit from an alternative: