You can banish 1 Level 5 or higher monster from your Graveyard; Special Summon this card from your hand, also you cannot Special Summon monsters from the Extra Deck for the rest of this turn. If this card is Tributed for a Tribute Summon: You can look at all Set cards your opponent controls. Your opponent cannot activate cards or effects in response to this effect's activation. You can only use each effect of "Lucius the Shadow Vassal" once per turn.
After looking at your opponent’s set cards you can then appropriately use removal for problem cards. Use cards like Nobleman of Crossout or Nobleman of Extermination to deal with set cards. Use Anti-Magic Arrows or Hey,Trunade! to deal with battle phase Traps.
Discarding Thunder Dragon is a good way of loading your graveyard with cost for special summoning Lucius while also thinning your deck.
Some monsters can destroy your opponent’s cards upon summoning. Use Lucius to tribute summon into them to know what you are destroying. Or to know what kind of monster you are attacking into and what backrow your opponent has in place.
|Actions||Reveals face-down cards|
|Banished categories||Banishes from Graveyard for cost / Banishes from your Graveyard|
|Monster/Spell/Trap categories||Prevents activation of your opponent's Effect Monsters / Prevents activation of your opponent's Spell Cards / Prevents activation of your opponent's Trap Cards / Prevents responding to its activation|
|Summoning categories||Special Summons itself from your hand / Prevents your Special Summons|