These cross over at a 1 to 10 ratio. Tenths of a point are recorded, but cannot be used. Also, an Immortal who receive DSPs from another Immortal does not have to roll unless he himself earns a Dark Side point. If an Immortal loses his head in a non-combat situation, his Quickening can either vanish or be absorbed by another Immortal nearby. Immortal Combat Immortals have a code of honor that all follow.
Swords are the most common weapons, but others can be used.
Penalties Immortals must try and hide their existance from the outside world, as it would be a shock to us normal folk. They do not age, and they cannot procreate. The watchers are a super-secret society that study the lives of Immortals and record what they see. It is a very ancient society, and unknown to most people mortal and Immortal alike. Each Immortal has an assigned Watcher, who tries to follow that Immortal everywhere he goes.