Play around with it, see how it works for you. Start your day with two 16 ounce glasses of water, before coffee or breakfast and drink plenty during the day. Drink a glass before lunch, and ditto before dinner. A gallon is certainly not too much, and again, if you live in a hot humid climate, it may not be enough. I have lived in both Texas - hot or hot and humid - and Minnesota - very cold but dry cold - and found that people did not drink enough water.
Players may also burn certain items in Bonfires to achieve effects. Bonfires serve as access points for Item Box drops. Due to the lack of a pause feature in Dark Souls 2, Bonfires are an integral point for players to take a break from play.
Soul Reapers are souls that have supernatural powers. As such, their bodies are composed of Spiritrons (spirit particles) instead of atoms. This means that just like most other types of spirits, they can only be seen by other spiritually aware entities, which excludes most humans.