Mysterious Pilot Licence (which no one really knows)
MPL (Multi-crew Pilot Licence) is a rating that you can only fly in Multi-Piloted aircraft. It is equal to the fATPL without the PPL or CPL benefits up to 1500 hours.
At the same time, this licence is valid with the company that you obtained your licence, again up to 1500 hours.
After finishing the course and 1500 hours your licence will be converted to ATPL and the bond will be broken.
You can fly in any airline you want after this, but as far as I know MPL does not come with any benefits of PPL or CPL.
Because in the training phase you are going to be spending less time flying in real aircrafts and more time in simulators.
Obviously, you can always talk with a flight school and complete the required flying hours (especially by paying a bit more and taking more test) and obtain those other licences too.