The Maschenny-style Lightning Spear technique that Ran uses is a Lightning Style technique invented by Maschenny Zahard, who made an appearance a while ago.
It’s a technique that turns Shinsu into a spear, so it grants the advantage of being able to take the Spear Bearer position without being armed with spears.
(Compared to ordinary shinsoo manipulation techniques, Lightning Spear techniques are much faster and have higher accuracy.)
As it allows one to participate in both short and long-range battles, it is considered to be one of the ‘ultimate spear techniques’.
The Maschenny-style Lightning Spear technique is only passed down in Maschenny's branch of the Khun Family, (in Ran's case, due to the Lightning Spear technique, his ranking as a Spear Bearer is higher than his ranking as a Fisherman.)
However, after becoming a Ranker,
it is very difficult to take on the role of a professional Spear Bearer with the Lightening Spear technique alone.
(Because the level of other Spear Bearers become that much higher)
So later on, they're used more as a support role in close-range battles...
In Maschenny Zahard’s case, her lightning Spear technique is faaaaar stronger than a usual High Ranker’s spear technique.
In other words, if you have Maschenny on your team, it's the same thing as having another High Ranker-level Spear Bearer on your Team.
Of course, the only person who can use the Maschenny-style Lightning Spear technique so proficiently is Maschenny Zahard herself ^^;