If your making a third promotion you need to set the fromvoc to the previous promotion, except the original vocation, which has the same fromvoc as itself.
Code:
Id = 1 -> ID = 5 -> ID = 9 -> ID = 13
Knight -> Elite Knight -> Slayer Knight -> Murderous Knight
fromvoc = 1 -> fromvoc = 1 -> fromvoc = 5 -> fromvoc = 9
data/weapons/weapons.xml -> Where to change levels and vocations to use each weapon.
data/movements/movements.xml -> Where to change level and vocation to use each armor.
good afternoon friend , I made the changes as you described , just on my server to fromvoc the knight and the knight elite are fromvoc = 4 , then getting the slayer fromvoc = 8 right? even making this change could not use the item .
weapon.xml
<melee id="22403" level="250" unproperly="1" function="default">
<vocation name="Knight"/>
<vocation name="Elite Knight" showInDescription="0"/>
<vocation name="Slayer Knight" showInDescription="0"/>
vocation.xml
<vocation id="8" clientid="1" name="Elite Knight" description="an elite knight" gaincap="25" gainhp="15" gainmana="5" gainhpticks="2" gainhpamount="20" gainmanaticks="1" gainmanaamount="10" manamultiplier="3.0" attackspeed="1300" basespeed="220" soulmax="200" gainsoulticks="15" fromvoc="4">
<formula meleeDamage="1.0" distDamage="1.0" defense="1.0" armor="1.0"/>
<skill id="0" multiplier="1.1"/>
<skill id="1" multiplier="1.1"/>
<skill id="2" multiplier="1.1"/>
<skill id="3" multiplier="1.1"/>
<skill id="4" multiplier="1.4"/>
<skill id="5" multiplier="1.1"/>
<skill id="6" multiplier="1.1"/>
</vocation>
<vocation id="9" clientid="3" name="Slayer Sorcerer" description="a slayer sorcerer" gaincap="10" gainhp="5" gainmana="30" gainhpticks="5" gainhpamount="5" gainmanaticks="2" gainmanaamount="20" manamultiplier="1.1" attackspeed="1600" basespeed="220" soulmax="100" gainsoulticks="120" fromvoc="5">
<formula meleeDamage="1.0" distDamage="1.0" defense="1.0" armor="1.0"/>
<skill id="0" multiplier="1.5"/>
<skill id="1" multiplier="2.0"/>
<skill id="2" multiplier="2.0"/>
<skill id="3" multiplier="2.0"/>
<skill id="4" multiplier="2.0"/>
<skill id="5" multiplier="1.5"/>
<skill id="6" multiplier="1.1"/>
</vocation>
<vocation id="10" clientid="4" name="Slayer Druid" description="a slayer Druid" gaincap="10" gainhp="5" gainmana="30" gainhpticks="2" gainhpamount="350" gainmanaticks="2" gainmanaamount="350" manamultiplier="1.1" attackspeed="30" soulmax="200" gainsoulticks="15" fromvoc="6">
<formula meleeDamage="3.0" distDamage="1.0" defense="2.0" armor="1.0"/>
<skill id="0" multiplier="1.5"/>
<skill id="1" multiplier="1.8"/>
<skill id="2" multiplier="1.8"/>
<skill id="3" multiplier="1.8"/>
<skill id="4" multiplier="1.8"/>
<skill id="5" multiplier="1.5"/>
<skill id="6" multiplier="1.1"/>
</vocation>
<vocation id="11" clientid="2" name="Slayer Paladin" description="a slayer Paladin" gaincap="20" gainhp="10" gainmana="15" gainhpticks="2" gainhpamount="350" gainmanaticks="2" gainmanaamount="350" manamultiplier="1.6" attackspeed="30" soulmax="200" gainsoulticks="15" fromvoc="7">
<formula meleeDamage="3.0" distDamage="2.0" defense="2.0" armor="1.0"/>
<skill id="0" multiplier="1.2"/>
<skill id="1" multiplier="1.2"/>
<skill id="2" multiplier="1.2"/>
<skill id="3" multiplier="1.2"/>
<skill id="4" multiplier="1.1"/>
<skill id="5" multiplier="1.1"/>
<skill id="6" multiplier="1.1"/>
</vocation>
<vocation id="12" clientid="1" name="Slayer Knight" description="a slayer Knight" gaincap="25" gainhp="15" gainmana="5" gainhpticks="2" gainhpamount="350" gainmanaticks="2" gainmanaamount="350" manamultiplier="4.0" attackspeed="30" soulmax="200" gainsoulticks="15" fromvoc="8">
<formula meleeDamage="3.3" distDamage="1.0" defense="2.5" armor="1.0"/>
<skill id="0" multiplier="1.1"/>
<skill id="1" multiplier="1.1"/>
<skill id="2" multiplier="1.1"/>
<skill id="3" multiplier="1.1"/>
<skill id="4" multiplier="1.4"/>
<skill id="5" multiplier="1.1"/>
<skill id="6" multiplier="1.1"/>
</vocation>
</vocations>