The Assembly creates and trains Heroes. It is there that Hero Factory FM is aired, mainly in the lobby of the tower below the training area. There are also Training Spheres inside the tower which project life like enemies for heroes young and old to hone in on their skills. This tower appears to be the central area where heroes are built or at the very least where Akiyama Makuro first started the company.
In addition to building heroes and providing them with their cores, the Assembly Tower is also used to refit armor for these robots. For instance if a hero's current plating is insufficient for the mission they are about to embark on, then they can go to the refitting area to replace their obsolete metal with better tools such as acid resistant armor (which was used against Corroder in the first four episodes), or any other experimental herotech. It is also know that mission managers like Zib work nearby, monitoring a hero's progress and making sure they are ready for battle. Apparently there is also a rule in the tower that a hero cannot leave without a fully charged quaza core, as scene when Zib prevented Stormer from helping with the Corroder crisis.
The Assembly Tower was seen in the very first Hero Factory commercial where Furno is being built by various mechanical arms. It is to be assumed that every hero has gone through this room more than a few times for upgrades or refitting, making it a vital section of HF headquarters. Whether there are other Hero Factories or Towers on other worlds has yet to be revealed, but considering the number of heroes we can assume that there are more. It is also revealed in the Lego magazine that Makuhero City does have it's own newspaper known as The Makuhero Star.
- Makuhero is a play on Make-a-Hero or more likely on the name of the creator of HF being 'Makuro.'