You can send 1 face-up LIGHT Normal Monster you control to the Graveyard; Special Summon this card from your hand or Graveyard. You can Tribute 1 "Noble Knight" monster; add 1 "Noble Arms" card from your Deck to your hand. You can only use this effect of "Ignoble Knight of Black Laundsallyn" once per turn. You can only control 1 "Ignoble Knight of Black Laundsallyn".
You can special summon Ignoble Knight Black Laundsallyn with Noble Knight Medraut’s effect. After Special summoning Ignoble Knight Black Laundsallyn, you can use his effect to tribute Medraut and search a Noble Arms card from your deck.
Normal Summon Artorigus and then special summon Gawayn, then you can special summon Laundsallyn by sending Artorigus to the graveyard. You can also replace Artorigus with any Noble Knight monster that is treated as a Normal monster on the field. Since your special summoned Gawayn would most likely be killed during your opponent’s turn, you can instead tribute him with Laundsallyn’s effect to search a Noble Arms card from your deck.