Try this
skilldata.txt:
"skill_begin skill_name=[s_dance_of_inspiration2] /* [Dance of Inspiration] */ skill_id=272 level=2 operate_type=A2 magic_level=46 effect={{p_hit;{all};4;diff}} operate_cond={} is_magic=1 mp_consume1=0 mp_consume2=0 cast_range=400 effective_range=-1 skill_hit_time=2.5 skill_cool_time=0 skill_hit_cancel_time=0.5 reuse_delay=0 activate_rate=-1 lv_bonus_rate=0 basic_property=none abnormal_time=120 abnormal_lv=1 abnormal_type=dance_of_inspiration attribute=attr_none effect_point=438 target_type=target affect_scope=single affect_range=1300 affect_limit={0;0} next_action=none debuff=0 ride_state={@ride_none} skill_end"
>>>>>>>>operate_cond=(no nned wepon) or you most add some duals to npc <<<<<<