Beauty/ Handsomeness: This race does not have anyone that could be considered ugly. Everyone is good-looking, though the level of that varies.
Biology and Society: This race is not human of course. They do not need to breathe nor do they need their heart to beat. These organs are to make them more human, which is why their form resembles a human as well. Their physical strength, if not controlled, alone can destroy some worlds in their "realms" and below. Not to mention their magic and aura.
Despite being given the gift to feel emotions (to give freedom and compassion for other races so they won't destroy them) they're way of thinking is often -not always- different from many beings ruled by what's called human nature. In the Empires there are no poor people.
Jobs are all voluntary and they are not a race that needs to pay each other to do work. As a pastime not to be bored, they form a society and do jobs and hobbies instead of wandering off by themselves, though they will leave from time to time.
Their loyalty towards their leaders is especially high and grows the more they know them. This is one of the reasons why there's rarely any power wars in or between Empires. Most wars are with the few races who know of their existence. These races are also incredibly powerful but still fall behind the Celestials.
Of course this doesn't mean that there aren't bad celestials. Though in those cases they normally aim for other races, there are still quite a few problems caused by Celestials that need to be handled both in the Empires and elsewhere.
Restrictions:
To avoid the death of innocents by Celestials, restrictions are placed on them. Celestials are unable to kill good or innocent people. They have the ability to see one's soul and only if it's covered by more than a half of darkness, will they be able to kill or cause great harm to the person. Extreme situations will allow for a few exceptions though.
Consequences:
"Guardians" ensure that these things do not happen and are responsible for punishing those who break these rules by stripping the Celestial of their power or killing them.
Realms:
As celestials grow older their body stays as that of a young adult for the rest of their life but their power grows. Because of this, their creator made different realms. When their power reaches a certain level, they move up realms and are not able to return to the lower ones. This avoids the destruction of a realm due to a Celestial's natural overwhelming power.
Guardians and Worlds:
Guardians are celestials in each realm chosen to look over the worlds. As there are many worlds which the celestials will want to visit (vacation, curiosity, missions...) the guardians look over it to make sure the celestials don't cause trouble.
If a celestial wants to enter a world, they will have to seal a certain amount of their power depending on the world's level. This is to avoid Celestials destroying worlds because the world couldn't handle their power. Not only their magic is limited and sealed, but sometimes also their physical strength. This may cause some physical changes like getting shorter.
Another rule is that if the world they enter has a certain fate or plot (protagonists and all), they are not allowed to make major changes. Like character development that is necessary for the plot, certain characters' deaths and major events.