So I thought about doing this :

1- use Foolish Burial to send Black Luster Soldier Envoy of the beginning to the graveyard
2- use Call of the Haunted to special summon him
3- I can't special summon him.
Is there something wrong here?

I started using Nekroz for the first time yesterday since they got hit and things (i just don't like meta)

1- I discarded Brionac to the grave to get Nekroz of Catastor

2- I discarded Catastor to the grave

3- I can't special summon Brionac

Black Luster Soldier - Envoy of the Beginning's effect:

Cannot be Normal Summoned/Set. Must first be Special Summoned (from your hand) by banishing 1 LIGHT and 1 DARK monster from your Graveyard. Once per turn, you can activate 1 of these effects.
● Target 1 monster on the field; banish that target face-up. This card cannot attack the turn you activate this effect.
● During the Damage Step, if this attacking card destroys an opponent's monster by battle: It can make a second attack in a row.

Brionac's effect:

You can Ritual Summon this card with any "Nekroz" Ritual Spell Card. Must be Ritual Summoned without using "Nekroz of Brionac", and cannot be Special Summoned by other ways. You can only use each of these effects of "Nekroz of Brionac" once per turn.
● You can discard this card; add 1 "Nekroz" monster from your Deck to your hand, except "Nekroz of Brionac".
● You can target up to 2 face-up monsters on the field that were Special Summoned from the Extra Deck; shuffle them into the Deck.

BLS can only be Special Summoned when it has been Special Summoned from your hand before through its effect. When that has been done, you can later on Special Summon it from the graveyard. Brionac can only be Special Summon when Ritual Summoned. Any other way of Special Summoning it is not able.