"Wight" refers to a spirit, ghost or any other supernatural being.
The story of "Skull Servant" is explained in Master Guide 3 card storylines.
This Deck's main strategy is to populate the Graveyard with "Wight" monsters to have a "King of the Skull Servants" with up to 20000 ATK.
Cards like "Armageddon Knight" and "Dark Grepher" are used to populate the Graveyard with "Wights" to increase the ATK of "King of the Skull Servants". "Wightprince" and "Wightbaking" have effects that activate when sent to the GY, which either send Wight monsters to the GY, or add them to the hand. Powerful Zombie support such as "Zombie Master", "Goblin Zombie", and "Mezuki" are required. "Wightmare" can be used to retrieve banished cards by discarding itself, either into the Graveyard for "King of the Skull Servants" or Special Summoning "The Lady in Wight".
The advantages of this Deck include its ability to produce extremely high-ATK monsters very quickly (which may not be affected by Spells or Traps if "The Lady in Wight" is on the field), as well as its resilience in Summoning said monsters repeatedly.
A major weakness is its total reliance on the Graveyard. If "Macro Cosmos" or "Dimensional Fissure" is in play, it can easily ruin your ability to power up "King of the Skull Servants". This was partially solved thanks to "Wightmare", which is capable of returning "Wight" monsters that are banished back to either the Graveyard or Summoning them to the field in exchange for discarding itself - especially helpful as it does not need to reach the Graveyard itself to work.