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He was introduced to the harsh cold reality of this planet earth since he was young. It is a dark, dark truth that his parent has been trying to keep it from him until they figured out that he's ready for it. But alas, fate is such a dick to a still young Dick.
But he grown accustomed to it. Being raised in Gotham by a bat and all. An abrupt change from the circus who seems to have endless journey of joy for him to walk upon until Tony Zucco existence came in with a big bang on his life of course.
And at the beginning, he thought that this must be the worst thing that ever happen to him and he's partly right. It's not that bad after all. It is amusing to see the Big Dark Scary Batman go around with that look that says "I took in a kid, Now what?" and there's Alfred Pennyworth who should be called Alfred Very-Worthy cause the Big Dark Scary Batman would be very much damned if the existence of Alfred Very-Worthy is erase off any planet in general.
Sure he live in this psychotic, dark and creepy world but that doesn't mean he needs to psychotic, dark and creepy right? he figured out this world need something to light up the mood in a good way.
So his childhood is not that golden, so he live in a creepy world, so he got a broody Bat but look on the more good bright side, he save life, he got a lot of good friends that he can count on.
Thinking of them as the 'light of his life' would be completely exaggerating but they are. They're not as literally as bright as the circus, but they 'light up the mood'. They became the lumière in his life.
The world is not that dark after all.