Bloody Line is a darkness transcendental skill that cuts in an area where the user is looking at.
Among the darkness-attribute transcendental skills, this transcendental has one of the highest required transcendental values. Therefore, it is usually only used by nastika. Although it is very useful in human form in a quite narrow range, since the range increases proportionaly to the body size, it's by far more powerful when used in sura form.
Hand gestures are usually used with this skill (more out of habit than anything else) but are not essential. Although the skill can be blocked physically, used on living creatures, Blood ignores the defense and cuts.
There are two methods for living creatures to avoid this transcendental. The first method is for the target to get a solid obstacle between themselves and the user. The second way is to avoid looking at the red line that appears prior to the cutting.
Because there is very short delay between the appearance of the red line and the cutting (not perceivable with the normal eye), it's only possible to avoid with extreme fast movement.