all crafting is dependent on luck. This means you get 2 armors that contain the elements that you wish to have in your crafted armor and you craft them together. Afterwards. the only thing that plays a role is the the star number of resulting armor and the star numbers of the starting armors. Meaning joining two 1-star armor has a better chance of creating a 2-star armor than joining two basic armors.
This also means that you have a chance to craft any armor by joining 2 basic armors, you just have a very low chance.
If you wish to craft living flame, look at the elements in it, get the uncommon armors (bronze star) and fuse them together. With luck you will get it. I was able to get it on my 2nd try.
Living Flame is a waste to fuse as you can craft it from materials won in Blazing Tides when you beat the Phoenix w/ a special attack and receive Phoenix feathers; plus you gain XP to help your knight level up. The plus version is released when the normal version is upgraded to lvl 15. The normal version has better stats than Embersteel when maxed and the plus versions of Living Flame and the other Big Four armors (i.e., Atlantean, Crius and Hydra Hunter) are better than the normal version of most 2* armor sets when comparing max stats. The Big Four + versions are the best way to advance through the Adventure levels, be competitive in the arena, and give you the best chance to beat the Epic Boss on tier 15 (usually once you get to be ~ lvl 40 and have several strong friends) to receive epic boss legendary armors; at least until you reach upper levels and begin to acquire additional legendary sets.
Now, all craftable 1* armors, like the Big 4 and other armors from the Adventure levels are worth 24EP (enhancement points) while non-craftable 1* armors (i.e., Volcanic Mantle, Flamestorm Finery, Wavecharmer's Mantle, and Wind Monarch's Robes) are worth 50EP. These are guaranteed minimum results from fusing the basic element armors (i.e., earth/fire, fire/air, water/spirit, and air/spirit, respectively); there are some 2* outcomes but in the end all are worth 50EP. Also, 3* and 4* armors are worth 90EP, while Fusion Boost armors are worth 180EP. All EP are for matching at least one element when enhanceing; otherwise, EP values decrease by ~20%.
I would just like to state ,for all you K'D nerds that it is possible to fuse a +. Oh and it's really useless to spend gems or gold on living as it is quite common, you can craft it from blazing tides and flaming wildwood, it's very weak, I've gotten hold of it four times and it's no different to any other armour