Without giving specifics away, a seismic event led to goblins achieving victory over the wood elves, which results in them occupying their palace and other settlements within the woods. How would the place evolve under 20 years of occupation from an entirely different race? Architecture wise, the walls and floor would still be in place. Elven statues however would be smashed or replaced with goblin replacements. Elf memorabilia would either be thrown out or some things like jewelry would be kept by the lead goblin.
That's a difficult question to answer, given that neither elves nor goblins are real. It very much depends on how goblins act in your world. In a world where goblins are comparatively unintelligent, a palace is just another big space for them to occupy. They wouldn't care about statues and the like. They'd probably keep the shiny things. In one where goblins are more intelligent and heirarchical, they may try to imitate the elves, and the goblin king might wear an elf crown.
In all fantasy, fantasy races are based on real life. Example: scholars argue that Tolkien's inspiration of his orcs and goblins were due to the climate of fear and hate during wartime. In a more obvious example: Scar and the hyenas in The Lion king were Nazis Back to your question.... as Nao said, its hard to determine or comment on how your goblins would affect your world, but it would be helpful to understand your parallels. Who/what were your inspirations for your goblins? What is their character? are they advance? do they have specific ideals? How is their military? Who/what is their leader? D the elves fall in line or do they resist the whole 20 years of occupation?
This is too open a question. There is no cultural context for either group. There is a huge gambit of possibilities in the given scenario. The gambit could range from a modern drug addict squat in an abandoned building, to attempts at cultural mimicry, or anything in between.
The inspirations for my goblins are Normans/Saxons and LOTR/DnD style goblins. They are thieves and tricksters. They are primitive and before their occupation resided in caves and the darkest parts of the woods. Their ideals are to replace the elves as rulers of the woods which they succeed in doing but the woods are slowly dying. They have a sizeable army and can call for more from nearby settlements. Their leader is half elf, half goblin but hates the elven side and was raised by goblins. A few elves are kept as slaves in the palace and most of the elven population either fled the woods altogether or squatted in caves. There have been attempts made to retake the palace but have failed to materialise.
From this description, I would expect the goblins to be more of a raider culture from a military stand point. So lots of hit and run tactics, and ambushes. With their numbers, any pitched fighting would be more wave tactics, when they can't avoid that type of fight.
It sounds like they lack a robust culture of their own to stick to, therefore I suggest they are likely to gradually adopt more and more of the customs of the established Elven culture, language, mores, but infusing that with their own warlike tendancies. For examples see the numerous barbarian conquerors of Egypt, all of whom were absorbed, the Mongols in China, and many many stepps warrior cultures that fell on softer more cultured lowland nations and became just another ruling class. For more inspiration I suggest reading HG Wells's nonfiction Outline of History, specifically his theory of 'communities of will' (your hobgoblins) vs 'communities of obedience' (elves). Even when a sophisticated culture conquers another sophisticated culture, unless they go in with a plan to do more than rule and get rich they usually end up adapting to their new land more than their land adapts to them. See: Helenics take Egypt, Normans take England, East India Co. takes India (before the Raj).
Maybe the goblins would vandalize the Elven statues if there are any. And if your goblins prefer less sunlight then maybe they'd use a lot of curtains or they'd lay bricks to make the windows smaller.
That would make sense if you model the goblins on some of the more extreme middle Eastern groups. The way the Taliban and ISIS destroyed historical sites, etc.
