The skill description, in most cases, only give the immediate requirement for the skill. For skills that are needed for the required skills they are not listed. i said mostly because we based the skill tree on the emulator files. This is how the skill sim make you get Faith level 10, it is required for Grand Cross and Grand Cross is required for Devotion, while you must have Devotion to have Sacrifice:

Faith Level 10
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Grand Cross Level 4
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Devotion Level 3
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Sacrifice Level 1 Available
It is assumed you need to read the requirement for Devotion to see what is needed before that. Same for Grand Cross. Because if you have Devotion Level 3 you must have everything required before that so there is no need to list the whole chain.
Also I should mention due to kRO skill names are used first, in this context
Sacrifice's iRO name is
Martyr's Reckoning.
Devotion's iRO name is
Sacrifice.