This build is made to be super tank Ymir, suborn magic damage or physical nothing goes through to build it in the middle of the game, it is possible tanking 3V1 smoothly is very good to hold lane when his allies are dead for example. So, use this build if your team for all damages, without brackets.
In the beginning you will not be tanker, just stay in the middle row evolving and gathering gold, help your lane partner if it is damage, it is always good to buy life potion if you want to play in a more attacking.
Halfway through the game your already Ymir will be with lots of life and lots of magic defense / physical execelente it is at this point you are ready to keep the front line of the fight, do not be afraid if your team is faster you will be able to stay at the forefront quietly! More probably care if you fall the team will have to retreat interoperable, so slight and is for tanking, tanking is not easy to say who knows tank NOT DIE!
At the end of the game you will be able tanking until the minotaur (hehe) sincerely if you have all the items made NOBODY knocks you off! With this build you safe everyone and stay ahead of your team to put fear into the enemy tank ignore the enemy tank just to lock the enemy Damage not get to their allies. With this is GG!