The unknown achievement is related to the shapeshifter recruiting the rival at the final confrontation and then attempting to create a offspring together in a human form, while the synergy requires using special hybrids due to fact you need non-duplicate characters with varied genes in order to get high ranks, easier if you play the shapeshifter due to genes counting for the effect, meaning they can attain the highest potential with it(and they do). Both reward with traits, one that adds the character in a non-elite form(which was a big deal when it was introduced due to elite tag being 1 per team rather than per species, now not so much beyond early summon/transform), while the synergy is a trait that allows changing the first element of spirits into a base species one, which is still lower than using special hybrids, but can make non-base species teams benefit from elemental bonus, at the cost of affecting their breeding capacity, since they end up making unpure species that you have to fuse in order to make them proper.
And even better, the adapt skill in skilltree is now free skill change on any character, unique or otherwise without getting adapted special, which is very flexible while others have to choose between a trait or a skill change for a adaption cost. That is good, since you can change the bred/fused characters skills that somehow got the undesirable ones, and ones that have less than you'd actually want at demand.
I really thirst for more challenge ranks/higher difficulty achievements with a system that unlocks multiple new ones to be added, so I can put my skills to the final test, and the powers that be to their highest potential. Would be fun to mix and match their modifiers for fun, or to take all of them to advance to the next tier, of which there should be more with accompanying rewards.
