One of the biggest draws for any monsters game is being able to collect a menagerie of powerful, cool, adorable, and terrifying creatures - whether that’s by catching them in balls, convincing them to join you through diplomacy, or recording them on cassette tapes.Dragon Quest Monsters: The Dark Princehas two methods.
The first is a classic: show off your strength and recruit monsters by beating them up. Monsters respect strength, that’s easy enough to understand. The second is Synthesis, where you take two monsters and combine them, with the result being a whole new, (hopefully) more powerful beast.

How To Unlock Synthesis
Despite being given access to two whole areas filled with monsters early on and being able to amass a very large collection, you can’t use Synthesis off the bat. First,you’ll need to pursue the main storyline.
There are three main challenges that you’ll have to overcome before you’re given the ability to Synthesise your monsters.Click the links belowif you’re struggling with any of the steps required.
As soon as you complete that final step, you’ll learn that you now haveaccess to Synthesis.
To access the Synthesis mechanic, you’ll need to return to Rosehill Tower, your teleporting base of operations.Talk to Monty in the basement here to accessSynthesis.
Once you unlock Synthesis,Roystonwill also be present in the Rosehill Tower basement - you can talk to him toaccess the monster depotwithout going all the way back to the Paddock.