How Volcano Location works?

Just explain me what means the +0.5, +1.0, etc etc... if multiplies or it's a percent or just it's a sum

Well, primarily these locations were meant as an aesthetic touch to fill in that black void around our houses. These stat bonuses are just that, bonuses that give a bit of an edge to these locations.

So really, you're paying mostly for that vanity environment around your home, it's not meant much of a utility incentive.

Try this:

http://www.spacetimestudios.com/show...ge-Calculation

Here how this works:

Starter House: 0.5 damage
Cottage House: 1.0 damage.
Lodge House: 1.5 damage.
Tavern House: 2.0 damage

Having a volcano is like having 1 extra para gem or the chaos that gives 2 dmg